OPERATION AND Products That Perform . . .By People Who Care … · screw chillers flooded products...
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Form No: USM0408B - 60Hz - 203-522Tons AIR COOLED ROTARY SCREW CHILLERS FLOODED FLOODED Products That Perform . . .By People Who Care ® ACFX 200-6 ACFX 220-6 ACFX 250-6 ACFX 280-6 ACFX 300-6 ACFX 330-6 ACFX 360-6 ACFX 420-6 ACFX 450-6 ACFX 480-6 ACFX 500-6 ACFX 530-6 INSTALLATION, OPERATION AND MAINTENANCE MANUAL INSTALLATION, OPERATION AND MAINTENANCE MANUAL 60 Hz 60 Hz
Transcript of OPERATION AND Products That Perform . . .By People Who Care … · screw chillers flooded products...
Form No: USM0408B - 60Hz - 203-522Tons
AIR COOLEDROTARYSCREW
CHILLERSFLOODEDFLOODED
Products That Perform . . .By People Who Care
®
ACFX 200-6ACFX 220-6ACFX 250-6ACFX 280-6ACFX 300-6ACFX 330-6ACFX 360-6ACFX 420-6ACFX 450-6ACFX 480-6ACFX 500-6ACFX 530-6
INSTALLATION,OPERATION ANDMAINTENANCEMANUAL
INSTALLATION,OPERATION ANDMAINTENANCEMANUAL
60 Hz60 Hz
TABLE OF CONTENTS
DESCRIPTION PAGE NO1.0 INTRODUCTION
1.1 Nomenclature............................................................................................................................................................. 4
2.0 INSTALLATION2.1 General ........................................................................................................................................................................ 7
2.1.1 Application Precautions.................................................................................................................................... 72.1.2 Chilled Water Flow........................................................................................................................................... 7
2.2 Inspection .................................................................................................................................................................... 72.3 Rigging ........................................................................................................................................................................ 7
2.3.1 General.............................................................................................................................................................. 72.3.2 Rigging & Moving............................................................................................................................................ 7
2.4 Space Requirements and Clearance .................................................................................................................... 92.4.1 General.............................................................................................................................................................. 92.4.2 ACFX................................................................................................................................................................ 9
2.5 Foundation................................................................................................................................................................ 142.6 Vibration Isolation ................................................................................................................................................. 142.7 Piping connections .................................................................................................................................................. 142.8 Electrical Wiring ..................................................................................................................................................... 142.9 Controls ..................................................................................................................................................................... 17
2.9.1 Connections .................................................................................................................................................... 172.9.2 Settings ........................................................................................................................................................... 17
2.10 Request For Start-Up Representative ............................................................................................................... 17
3.0 OPERATION3.1 General ...................................................................................................................................................................... 183.2 Unit piping ................................................................................................................................................................ 183.3 System Water Flow Rate ...................................................................................................................................... 183.4 Standard Ambient Unit Operation (65°F Minimum Ambient)
Including Overnight Shut Down and Morning Restart............................................................................... 183.4.1 Air Cooled Package Chiller Start-Up ............................................................................................................. 18
3.5 System Start Up....................................................................................................................................................... 183.6 Shut-Down (Overnight Or Weekend) ............................................................................................................... 223.7 Seasonal Shut-Down Procedure.......................................................................................................................... 223.8 Seasonal Start-up Procedure ............................................................................................................................... 223.9 Safety Relief Valves ................................................................................................................................................ 233.10 Refrigeration Cycle- Multiple Compressor ACFX ........................................................................................ 233.11 Fan Cycling .............................................................................................................................................................. 233.12 Liquid Injection....................................................................................................................................................... 233.13 Hydraulic Capacity Control System.................................................................................................................. 23
4.0 ELECTRICAL4.1 Electrical Data......................................................................................................................................................... 254.2 Wiring Diagram ...................................................................................................................................................... 254.3 Typical Operation................................................................................................................................................... 254.4 Microcomputer Controller .................................................................................................................................. 31
4.4.1 To Display Data From The Menu ................................................................................................................... 314.4.2 To Reset All Control Points To Computer Control ........................................................................................ 324.4.3 To Display Ala rms .......................................................................................................................................... 324.4.4 To Become Authorized ................................................................................................................................... 324.4.5 To Alter Setpoint Data.................................................................................................................................... 324.4.6 To Calibrate Temperature And Pressure Sensors ........................................................................................... 324.4.7 To Set Date And Time .................................................................................................................................... 334.4.8 To Display Data Without Accessing Menu .................................................................................................... 334.4.9 Unit Schedule Of Operation............................................................................................................................ 33
TABLE OF CONTENTS
DESCRIPTION PAGE NO
4.5 Control Functions ................................................................................................................................................... 344.5.1 Chilled Water Pump Interlock And Flow Switch (CWP And CWFS)........................................................... 344.5.2 Customer Interlock.......................................................................................................................................... 344.5.3 Anti-Recycle Timer (Microcomputer)............................................................................................................ 344.5.4 Load Control (Microcomputer)....................................................................................................................... 344.5.5 Ramp Control (Microcomputer) ..................................................................................................................... 354.5.6 Current Limiting (Microcomputer)................................................................................................................. 364.5.7 Staging Control (Microcomputer)................................................................................................................... 364.5.8 Manual lead-Lag Control (Microcomputer) ................................................................................................... 364.5.9 Manual Load-Unload Control (Microcomputer) ............................................................................................ 364.5.10 Chilled Water Reset And Customer Control Interlock (Optional).................................................................. 364.5.11 Variable Fan Speed Control (Optional) .......................................................................................................... 374.5.12 Sump Heater Control....................................................................................................................................... 37
4.6 Safety Functions ...................................................................................................................................................... 374.6.1 Control Power Loss (Microcomputer)............................................................................................................ 374.6.2 Low Pressure Cut-Off (Microcomputer)......................................................................................................... 374.6.3 Evaporator Freeze Shutoff (Microcomputer).................................................................................................. 374.6.4 High Pressure Cut-Off (Microcomputer)........................................................................................................ 374.6.5 Oil Level Sensor (LS) ..................................................................................................................................... 374.6.6 High Oil Temperature Thermostat (12 TAS).................................................................................................. 384.6.7 Motor Temperature Protector (1TAS) ............................................................................................................ 384.6.8 Overload Protector (OL) ................................................................................................................................. 384.6.9 Phase Control Relay (PCR)............................................................................................................................. 384.6.10 Sensor Alarm (Microcomputer)...................................................................................................................... 384.6.11 No-Stop Alarm (Microcomputer) ................................................................................................................... 384.6.12 Low Differential Pressure Alarm (Microcomputer) ....................................................................................... 38
5.05.0 MAINTENANCE5.1 General ...................................................................................................................................................................... 39
5.2 Periodic Inspection................................................................................................................................................. 39
5.3 Monthly Inspection................................................................................................................................................ 39
5.4 Vessel Maintenance................................................................................................................................................ 395.4.1 General............................................................................................................................................................ 395.4.2 Water Side Cleaning Of Cooler...................................................................................................................... 39
5.5 Air Cooled Condenser Cleaning ......................................................................................................................... 39
5.6 Electrical Malfunction .......................................................................................................................................... 41
5.7 Refrigerant Charge................................................................................................................................................ 41
5.8 Oil Charge ................................................................................................................................................................ 41
5.9 Troubleshooting ...................................................................................................................................................... 42
5.10 Sample Log Sheet ................................................................................................................................................... 43
SCHEMATIC DIAGRAM, GRAPH AND TABLE
DESCRIPTION PAGE NO
Figure 2.3.2 Typical Rigging.................................................... 8Figure 2.4.1 Space Requirements.............................................. 9Figure 2.4.2 Dimensional Data............................................... 11Figure 2.5 Isolator Location ................................................ 15Figure 2.5A Isolator Location ................................................ 16Figure 2.5B Isolator Point Load Data...................................... 16Figure 3.2 Typical Piping Schematic .................................... 19Figure 3.3 Cooler Water Pressure Drop ................................ 21Figure 3.13 Compressor Capacity Control Detail..................... 24Figure 4.2 Typical Wiring Schematic................................... 27
DESCRIPTION PAGE NO
Table 1.1 Physical Specifications..........................................5
Table 4.2 Control Data Sheet ..............................................31
Table 4.5.5 Sample Ramp Times (Minutes) .............................35
Table 5.4.2 R-22 P ressure/Temperature Properties...................40
1.0 INTRODUCTION
This manual is prepared to provide all the necessary information forinstallation, operation and maintenance of the latest generation of theDunham-Bush medium screw compressor air-cooled packaged chillers.
To utilize this manual effectively, you must first identify your unit
model from the unit nameplate.
Your Dunham-Bush package has been manufactured under a careful
quality control system. If the package is installed, operated andmaintained with care and attention to the instructions contained herein,it will yield many years of satisfactory service.
It is assumed that the user of this manual and those who install, operateand maintain this equipment are experienced and qualified airconditioning equipment personnel.
1.1 NOMENCLATURE
AC F X 250 - 6 S R
Air Cooled Chiller
Flooded Evaporator
Screw Compressor
Nominal TonsTwin Compressors = 200, 220, 250,
280, 300, 330,360
Three Compressors = 420, 450, 480,500, 530
Blank - R22R - R134a
S - Standard UnitQ - Special Unit
5 = 50Hz6 = 60Hz
1.0 INTRODUCTION
TABLE 1.1 PHYSICAL SPECIFICATIONS
MODEL ACFX 200-6 ACFX 220-6 ACFX 250-6 ACFX 280-6 ACFX 300-6 ACFX 330-6
COMPRESSOR
MODEL (QTY) MSC1210(2) MSC 1210(1)MSC 1212(1)
MSC 1212(2) MSC 1212(1)MSC 1215(1)
MSC 1215(2) MSC 1215(1)MSC 1218(1)
RPM 3500 3500 3500 3500 3500 3500
OIL CHARGE (QTY) GAL 10.50 (2) 10.50 (1)10.25 (1)
10.25 (2) 10.25 (1)12.50 (1)
12.50 (2) 12.50 (2)
SUMP HEATER (QTY) kW 0.4 (2) 0.4 (2) 0.4 (2) 0.4 (2) 0.4 (2) 0.4 (2)
NOMINAL CAPACITY TR 203.3 222.4 250.2 274.9 301.1 326.7
COMPRESSOR KWI 216.8 238.7 259.7 282.3 306.6 339.1
FAN KWI 22.8 26.6 30.4 30.4 30.4 34.2
UNIT EER 10.18 10.06 10.35 10.55 10.72 10.50
MIN. % UNIT CAPACITYREDUCTION
12.50% 13.30% 12.50% 13.20% 12.50% 13.00%
EVAPORATOR
MODEL (QTY) EF14102M076KAG (2)
EF16102M098KAG (2)
EF18102M128KAG (2)
EF18102M128KAG (2)
EF18102M128KAG (2)
EF18102M144KAG(2)
WATER CONNECTOR INCH 6 6 8 8 8 8
NOM. WATER FLOW (GPM)/ PD(FT IN WG)
501 /(7.9 X 2)
556 /(6.2 X 2)
617 /(4.4 X 2)
684 /(5.3 X 2)
760 /(6.5 X 2)
828/(6.2 X 2)
MIN/MAX WATER FLOW (GPM) 222 / 886 288 / 1150 378 / 1500 378/ 1500 378/ 1500 425/ 1680
MIN/MAX WATER PD (FT IN WG) (1.8/ 22.0)X 2
(1.9/ 24.0)X 2
(1.8/ 22.2)X 2
(1.8/ 22.2)X 2
(1.8/ 22.2)X 2
(1.8/ 22.5)X 2
CONDENSER
COIL ROWS DEEP/ TOTAL FAFT²
3 / 282.3 3 / 329.4 3 / 376.4 3 / 188.24 / 188.2
4 / 376.4 4/423.5
NO OF FAN 12 14 16 16 16 18
FAN DIA (QTY) INCH 31.5 (12) 31.5 (14) 31.5 (16) 31.5 (16) 31.5 (16) 31.5 (9),31.5 (9)
FLA , AMP (QTY) 3.6 (12) 3.6 (14) 3.6 (16) 3.6 (16) 3.6 (16) 3.6 (18)
*MIN. AMBIENT TEMPERATURE(°F) AT MIN. LOAD
65 65 65 65 65 65
GENERAL
UNIT LENGTH INCH 322.5 365 402 402 402 444
UNIT WIDTH INCH 88 88 88 88 88 88
UNIT HEIGHT INCH 96 96 96 96 96 96
SHIPPING WEIGHT LBS 16035 18623 20713 21596 22522 23080
OPERATING WEIGHT LBS 16494 19218 21479 22362 23288 23900
OPERATING CHARGE R-22 LBS 472 524 582 644 716 780
* 45°F WITH SOLENOID CONTROL AND FAN CYCLING.
1.0 INTRODUCTION
MODEL ACFX 360-6 ACFX 420-6 ACFX 450-6 ACFX 480-6 ACFX 500-6 ACFX 530-6
COMPRESSOR
MODEL (QTY) MSC 1218(2) MSC 1212(1)MSC 1215(2)
MSC 1215(3) MSC 1215(2)MSC 1218(1)
MSC 1215(1)MSC 1218(2)
MSC 1218(3)
RPM 3500 3500 3500 3500 3500 3500
OIL CHARGE (QTY) GAL 12.50 (2) 10.25 (1)12.50 (2)
12.50 (3) 12.50 (3) 12.50 (3) 12.50 (3)
SUMP HEATER (QTY) kW 0.4 (2) 0.4 (3) 0.4 (3) 0.4 (3) 0.4 (3) 0.4 (3)
NOMINAL CAPACITY TR 355.4 417.2 446.9 472.5 500.1 521.7
COMPRESSOR KWI 373.9 434.7 458.0 494.1 530.0 565.1
FAN KWI 34.2 54.0 54.0 60.0 66.0 72.0
UNIT EER 10.45 10.24 10.47 10.23 10.47 9.83
MIN. % UNIT CAPACITYREDUCTION
12.50% 5.90% 8.33% 7.80% 7.40% 8.33%
EVAPORATOR
MODEL EF20102M180KAG(2)
EF24125H298KAJ
EF26125H336KAJ
EF28125H358KAJ
EF28125H378KAJ
EF28125H395KAJ
WATER CONNECTOR INCH 8 8 10 10 10 10
NOM. WATER FLOW (GPM)/ PD(FT IN WG)
898/(5.2 X 2)
1022/ 18.5 1089/ 17.0 1156/ 17.3 1224/ 17.3 1291/ 17.6
MIN/MAX WATER FLOW (GPM) 525/ 2100 299/ 1496 329/ 1643 350/ 1750 370/ 1848 387/ 1931
MIN/MAX WATER PD (FT IN WG) (1.9/ 24.2) X 2 2.0/ 37.0 1.9/ 36.0 2.0/ 36.5 2.0/ 36.5 2.0/ 36.5
CONDENSER
COIL ROWS DEEP/ TOTAL FAFT²
4/423.5 3/192.5,4/385.0
4/577.5 4/577.5 4/577.5 4/577.5
NO OF FAN 18 18 18 18 18 18
FAN DIA. (QTY) INCH 31.5 (18) 31.5 (6),33.9 (12)
33.9 (18) 33.9 (18) 33.9 (18) 33.9 (18)
FLA , AMP (QTY) 3.6 (18) 4.3 (18) 4.3(18) 4.3(12),5.7(6)
4.3(6),5.7(12)
5.7(18)
*MIN. AMBIENT TEMPERATURE(°F) AT MIN. LOAD
65 65 65 65 65 65
GENERAL
UNIT LENGTH INCH 444 473 473 473 473 473
UNIT WIDTH INCH 88 88 88 88 88 88
UNIT HEIGHT INCH 96 118 118 118 118 118
SHIPPING WEIGHT LBS 24595 28858 29991 32036 33179 34308
OPERATING WEIGHT LBS 25610 29767 31032 33178 34362 35527
OPERATING CHARGE R-22 LBS 846 963 1025 1089 1152 1216
* 45°F WITH SOLENOID CONTROL AND FAN CYCLING.
2.0 INSTALLATION
2.1 GENERALPackaged chillers are designed to cool water orother non-corrosive liquid. The liquid to becooled is to be circulated through the tubes of arefrigerant evaporator where the temperature isreduced to the desired level. The heat absorbed bythe refrigerant in the evaporator is rejected via thecondenser coils where it raises the temperature ofcross flow air.
Care should be taken to see that the equipment isproperly installed and adjusted. An installer oroperator should first be familiar with theinformation contained in this manual.
2.1.1 APPLICATION PRECAUTIONS
The following instructions are intended tohelp ensure that your water chillingmachine performs adequately.
2.1.2 CHILLED WATER FLOW
The Dunham-Bush ACFX PackagedWater Chiller is designed for constantchilled water flow rate, even when thecooling load varies. The machine willgenerally perform satisfactorily withsteady flow rates deviating from design byas much as ±10%. However, varying waterflow rates can cause instability in controlwhich will result in undesirable systemeffects, particularly poor control of leavingchilled water temperature. If two-wayvalves are used to control flow through thecooling coils, some means such as anautomatic modulating valve should beprovided in the system to maintain steadyflow through the cooler.
2.2 INSPECTIONWhen the equipment is delivered, it is importantthat the following inspection be implemented inthe presence of the forwarder’s representative.
1.) Check all crates and cartons received againstthe Bill of Lading/ Shipping Papers to be surethey agree.
2.) Check the model number and the electricalcharacteristics on the nameplate to determineif they are correct.
3.) Check for freight damage, shortages or otherdiscrepancies and note them on the deliveryreceipt before signing.
In the event of any damage, a damage claimshould be filed immediately by the purchaser.
2.3 RIGGING2.3.1 GENERAL
Each unit has been carefully tested at thefactory where every precaution is taken toensure that the unit reaches you in perfectcondition. It is very important that theriggers and movers use the same care andprecaution in moving the equipment intoplace. Make sure that chains, cables orother moving equipment are placed so asto prevent damage to the unit or piping.The refrigerant piping must not be used asa ladder or a handle. Do not attach a chainhoist sling to the piping or equipment.Move the unit in an upright position andlet it down gently from trucks or rollers.
2.3.2 RIGGING AND MOVING
Any unit mounted on skids may be movedwith a forklift, but care must be taken notto damage the unit with forks. The skidsshould not be removed until the unit is atits final location.
The ACFX model is to be rigged throughthe holes in the base side rails. In all cases,spreader bars must be used betweenrigging lines to prevent damage to thecoils or fan deck. The unit must be liftedusing All Rigging Points. Refer toRigging Instructions on Figure 2.3.2.
All models can be pushed or pulled (withchains) from the control box end only.Truck forks must be kept level and nottilted back. Do not raise the unit end bymore than 2" above the floor.
2.0 INSTALLATION
FIGURE 2.3.2 TYPICAL RIGGING
2.0 INSTALLATION
2.4 SPACE REQUIREMENTSAND CLEARANCE
2.4.1 GENERALThe dimensional data and clearancesshown in Figure 2.4.1 are useful fordetermining space requirements. The unitshould be placed to make the clearancenoted available for proper servicing.Failure to allow these clearances willresult in higher costs for operation,maintenance and repair.
2.4.2 ACFXThe dimensional data are shown in Figure2.4.2 and space requirements are shownin Figure 2.4.1. The most importantconsideration which must be taken intoaccount when deciding upon location ofair cooled equipment is provision for
ample supply of ambient air to thecondenser, and removal of heated airfrom the condenser area. If this essentialrequirement is not met, it will result inhigher condensing temperatures, whichwill cause poor operation, higher powerconsumption and possibly, eventualfailure of the equipment. Units must notbe located in the vicinity of steam, hot airor fume exhausts.Another consideration which must betaken into account is that the unit shouldbe mounted away from noise sensitivespaces and must have adequate support toavoid vibration and noise transmissioninto the building. Units should bemounted over corridors, utility areas, restrooms or other auxiliary areas wheresound levels are not an important factor.Sound and structural consultants shouldbe retained for recommendations oncritical installations.
FIGURE 2.4.1 SPACE REQUIREMENTS
WALLS OR OBSTRUCTIONS
The unit should be located so that air may circulate freely and not be recirculated. For proper air flowand access all sides of the unit must be at least six feet away from any wall or obstruction. It ispreferred that this distance be increased whenever possible. Care should be taken to see that amplespace is left for maintenance work through access doors and panels. Overhead obstructions are notpermitted. When the unit is in an area where it is enclosed by three walls the unit must be installed asindicated for units in a pit.
72"[1829mm] MIN.
2.0 INSTALLATION
FIGURE 2.4.1 SPACE REQUIREMENTS
Single Pit (See Note 2)
Double Pit (See Note 2)
Multi Pit
Corner Wall
Notes:1.) All dimensions are the minimum,
unless otherwise noted.
2.) Pit installations are not re-commended. Re-circulation of hotcondenser air, combined withsurface air turbulence cannot bepredicted. Hot air re-circulation willseverely affect unit efficiency ratio(EER) and can cause high pressureor fan motor temperature trips.Dunham-Bush will not beresponsible for ducting fans to ahigher level to alleviate the abovementioned conditions.
3.) ACFX 200-6 is shown in thisdrawing.
96"[2438mm] MIN.
72"[1829mm] MIN.48"[1219mm]MIN.
72"[1829mm] MIN.
48"[1219mm]MIN.
84"[2134mm] MAX.72"[1829mm]
MIN.72"[1829mm]
MIN.
84"[2134mm] MAX.96"[2438mm]
MIN.72"[1829mm]
MIN.72"[1829mm]
MIN.
AIR IN AIR IN
AIR IN AIR IN
14 3/4" [375]
365" [9271]
AIR OUT
88" [2235]
86" [2184]
6 NOS OF 2 1/2"[63.5]ØLIFTING HOLES ON BOTHSIDE OF BASE FRAME.
18" [457]163" [4140]163" [4140]21" [533]
22" [559]147 1/2" [3746]147 1/2" [3746]48" [1219]
6 NOS OF 3/4"[19.1]ØMOUNTING HOLES FORSPRING ISOLATORS.
34 1/2" [876] 220" [5588]
96" [2438]
6" [152]
CONTROL/POWERPANEL
8" [203]
AIR OUT
88" [2235]
86" [2184]
6 NOS OF 2 1/2"[63.5]ØLIFTING HOLES ON BOTHSIDE OF BASE FRAME.
18" [457]141 3/4" [3600]141 3/4" [3600]21" [533]
28" [711]123 1/4" [3131]123 1/4" [3131]48" [1219]
6 NOS OF 3/4"[19.1]ØMOUNTING HOLES FORSPRING ISOLATORS.
32" [813] 220" [5588]
96" [2438]
6" [152]
CONTROL/POWERPANEL
8" [203]
AIR IN AIR IN
AIR IN AIR IN
322 1/2" [8191]
13 3/4" [350]
2.0 INSTALLATION
FIGURE 2.4.2 DIMENSIONAL DATA
ACFX 200-6
ACFX 220-6
NOTE : ALL DIMENSIONS ARE IN INCHES [MM].
AIR OUT
88" [2235]
86" [2184]
6 NOS OF2 1/2"[63.5] Ø
88" [2235]
8 NOS OF 3/4"[19.1] ØMOUNTING HOLES FORSPRING ISOLATORS.
34 1/2" [876]
220" [5588]
CONTROL/POWERPANEL
8" [203]
402" [10211]
28" [711]118" [2997] 120" [3048] 118" [2997] 18" [457]
40" [1016]141" [3581]141" [3581]80" [2032]
6" [152]
96" [2438]
AIR IN AIR IN
AIR IN AIR IN
BASE FRAME.ON BOTH SIDE OFLIFTING HOLES
100" [2540]
162" [4115]
444" [11278]
26" [660]
80" [2032]
100" [2540]
162" [4115]
SPRING ISOLATORS.MOUNTING HOLES FOR10 NOS OF 3/4"[19.1]Ø
100" [2540] 100" [2540]
AIR IN
AIR INAIR IN
AIR IN
AIR IN
AIR IN
6" [152]
96" [2438]
86" [2184]
88" [2235]
18" [457]
40" [1016]
2 1/2"[63.5]Ø
BASE FRAME.BOTH SIDE OFLIFTING HOLES ON
6 NOS OF
8" [203]
AIR IN
AIR IN
88" [2235]
AIR OUT
PANELCONTROL/ POWER
220" [5588]76 1/2" [1943]
2.0 INSTALLATION
ACFX 250-6, 280-6, 300-6
ACFX 330-6, 360-6
NOTE : ALL DIMENSIONS ARE IN INCHES [MM].
ISO
LAT
OR
S.
FOR
SP
RIN
GM
OU
NTI
NG
HO
LES
12 N
OS
OF
3/4"
[19.
1]Ø
AIR
IN
AIR
IN
AIR
IN
AIR
IN
PA
NE
LC
ON
TRO
L/ P
OW
ER
6 N
OS
OF
2 1/
2"[6
3.5]
Ø
BA
SE
FR
AM
E.
BO
TH S
IDE
OF
LIFT
ING
HO
LES
ON
AIR
IN
AIR
IN
AIR
OU
T
473"
[120
14]
176
1/2"
[448
3]
80" [
2032
]
A
40" [
1016
]
80" [
2032
]17
6 1/
2" [4
483]
80" [
2032
]80
" [20
32]
INLE
T/O
UT
LET
ON
SA
ME
SID
E
80" [
2032
]
118"
[299
7]
6" [1
52]
88" [
2235
]
86" [
2184
]
40" [
1016
]
33" [
838]
80" [
2032
]
8" [2
03]
2.0 INSTALLATION
WA
TER
CO
NN
.S
IZE
8 [2
03]
10 [2
54]
10 [2
54]
10 [2
54]
10 [2
54]
A
17 3
/4[4
51]
19 5
/8[4
99]
19 3
/4[5
02]
19 3
/4[5
02]
19 3
/4[5
02]
AC
FX
420
-6, 4
50-6
, 480
-6, 5
00-6
, 530
-6
MO
DE
LA
CF
X
420-
6
450-
6
480-
6
500-
6
530-
6
NO
TE:
ALL
DIM
EN
SIO
NS
AR
EIN
INC
HE
S [M
M].
2.0 INSTALLATION
2.5 FOUNDATIONRefer to index for unit dimensions and loadpoints. Foundations must be level for properoperation and functioning of controls andprovisions must be made for supporting theindividual load points as shown in the unitdimensions. Roof mounted units must besupported on adequate steel structure. If units arelocated on the ground level, a concrete base isrecommended.
2.6 VIBRATION ISOLATIONUnder certain critical conditions. it may benecessary to install vibration isolators under thebase of the Packaged Chiller.
Rubber-in-shear or spring vibration isolators areoffered as optional items. When spring isolatorsare used, flexible connections must be installed inthe water piping system and in the refrigerantlines of split systems. Note: These flexibleconnectors must be suitable for the fluid andpressures involved.
All external pipings must be supported by springmounted hangers and any piping which goesthrough the wall, ceiling or floor should beproperly sheathed to prevent transmission ofpiping vibration to the structure.
When spring isolators are used, electrical serviceto the unit must also be flexibly connected bymeans of a 36" section of flexible conduit.
2.7 PIPING CONNECTIONSRefer to the dimensional drawings for waterpiping connection locations. After the unit hasbeen leveled and isolators (if any) installed &adjusted, connect cooler water piping, keeping inmind that the cooler tubes may require cleaningor replacement at some future date, andremovable sections of piping will be required topermit cooler head removal.
Piping must be supported to avoid excess stresson the cooler heads. Cut piping holes in the panelat the end of the unit, if there is any. Install air
vent points to permit complete air purging of thechilled water circuit. Install drain valves insimilar low points to facilitate complete watersystem drainage. Install temperature & pressureindicators in the water piping at the unit tomonitor water flow. Install shut-off valves toisolate the unit from the piping system during unitservicing.
Note: Due to possible high pressures resultingfrom rising temperatures, do not close shut-offvalves with cold water in the cooler.
It is important that the chilled water system becleaned before startup to avoid collecting debrisin the cooler. After filling the system with water(or a glycol solution), start the pump, bleed offthe trapped air, and check for proper flow rate bymeasuring water pressure drop across cooler.
NOTE: WATER QUALITY - ACFX
Coolers used in these packages are madeof steel, copper and brass and aresuitable for operation with well-maintained water systems. However, ifthe fluid used in cooler is corrosive, highin mineral content or entrained solids,the water can cause reducedperformance and even failure of heatexchangers. Therefore, it may benecessary to obtain the services of awater treatment consultant and toprovide and maintain water treatment.This is particularly important with glycolsolution systems.
2.8 ELECTRICAL WIRING
In connecting power wiring to the unit, thefollowing precautions should be taken:
1.) All field wiring is to be in accordance withthe National Electric Code and must complywith state and local codes. See Electrical Datafor minimum circuit ampacity and fuse size.
2.0 INSTALLATION
FIGURE 2.5 ISOLATOR LOCATION
ACFX 200-6, 220-6
ACFX 250-6, 280-6, 300-6
ACFX 330-6, 360-6
ACFX 420-6, 450-6, 480-6, 500-6, 530-6
2.0 INSTALLATION
TABLE 2.5A ISOLATOR LOCATION
Unit Model Dimensions – Inches [mm]
ACFX A Dim. B Dim. C Dim. D Dim. E Dim. F Dim. G Dim. H Dim.
200-6 86 [2184] 18 [457] 141 3/4 [3600] 141 3/4 [3600] 21 [533] - - -
220-6 86 [2184] 18 [457] 163 [4140] 163 [4140] 21 [533] - - -
250-6 86 [2184] 18 [457] 118 [2997] 120 [3048] 118 [2997] 28 [711] - -
280-6 86 [2184] 18 [457] 118 [2997] 120 [3048] 118 [2997] 28 [711] - -
300-6 86 [2184] 18 [457] 118 [2997] 120 [3048] 118 [2997] 28 [711] - -
330-6 86 [2184] 18 [457] 100 [2540] 100 [2540] 100 [2540] 100 [2540] 26 [914] -
360-6 86 [2184] 18 [457] 100 [2540] 100 [2540] 100 [2540] 100 [2540] 26 [914] -
420-6 86 [2184] 33 [838] 80 [2032] 80 [2032] 80 [2032] 80 [2032] 80 [2032] 40 [1016]
450-6 86 [2184] 33 [838] 80 [2032] 80 [2032] 80 [2032] 80 [2032] 80 [2032] 40 [1016]
480-6 86 [2184] 33 [838] 80 [2032] 80 [2032] 80 [2032] 80 [2032] 80 [2032] 40 [1016]
500-6 86 [2184] 33 [838] 80 [2032] 80 [2032] 80 [2032] 80 [2032] 80 [2032] 40 [1016]
530-6 86 [2184] 33 [838] 80 [2032] 80 [2032] 80 [2032] 80 [2032] 80 [2032] 40 [1016]
TABLE 2.5B ISOLATOR POINT LOAD DATA
UnitModel Point Load – Lbs [Kg]
TotalOperating
ACFXPos. #1 Pos. #2 Pos. #3 Pos. #4 Pos. #5 Pos. #6 Pos. #7 Pos. #8 Pos. #9 Pos. #10 Pos. #11 Pos. #12
WeightLbs [Kg]
200-6 3010[1365] 2801[1270] 2591[1175] 2486[1127] 2697[1223] 2907[1319] - - - - - - 16494[7480]
220-6 3428[1555] 3279[1487] 3129[1419] 2978[1351] 3129[1419] 3279[1487] - - - - - - 19218[8716]
250-6 2743[1244] 2744[1245] 2745[1245] 2746[1245] 2623[1190] 2625[1190] 2626[1191] 2628[1192] - - - - 21479[9741]
280-6 2801[1271] 2827[1282] 2853[1294] 2879[1306] 2758[1251] 2753[1249] 2749[1247] 2744[1244] - - - - 22362[10142]
300-6 3001[1361] 2981[1352] 2960[1343] 2940[1333] 2818[1278] 2841[1288] 2863[1299] 2886[1309] - - - - 23288[10562]
330-6 2514[1140] 2475[1123] 2436[1105] 2397[1087] 2358[1069] 2261[1025] 2303[1044] 2345[1063] 2386[1082] 2428[1101] - - 23900[10840]
360-6 2680[1216] 2645[1200] 2609[1183] 2574[1167] 2538[1151] 2441[1170] 2477[1124] 2514[1140] 2550[1157] 2587[1173] - - 25610[11616]
420-6 2652[1203] 2595[1177] 2539[1152] 2483[1126] 2426[1100] 2370[1075] 2257[1023] 2334[1059] 2412[1094] 2489[1129] 2567[1164] 2644 [1199] 29769[13501]
450-6 2694[1222] 2659[1206] 2623[1190] 2588[1174] 2553[1158] 2518[1142] 2407[1092] 2471[1121] 2534[1149] 2598[1178] 2662[1207] 2725[1236] 31032[14073]
480-6 2917[1323] 2863[1299] 2809[1274] 2755[1250] 2702[1225] 2648[1201] 2543[1154] 2625[1191] 2707[1228] 2789[1265] 2870[1302] 2952[1339] 33178[15047]
500-6 2993[1357] 2947[1337] 2902[1316] 2856[1295] 2811[1275] 2766[1254] 2661[1207] 2736[1241] 2811[1275] 2885[1308] 2960[1342] 3035[1376] 34362[15583]
530-6 3016[1368] 2999[1360] 2983[1353] 2967[1345] 3086[1338] 2934[1331] 2830[1283] 2877[1305] 2924[1326] 2970[1347] 3017[1368] 3064[1390] 35527[16112]
2.0 INSTALLATION
2.) Check unit wiring for damage and all terminalconnections for tightness. Unit terminalblocks are to be connected with copperconductors only, sized per ampacity listed onunit data plate.
3.) Connections to unit should match the unitnameplate in volts, phase, and Hertz. Voltagemust not vary beyond ±10% of nameplatevalue and voltage imbalance between phasesmust not exceed 2% at any time duringoperation of the unit.
4.) Phase sequence to connectors L1, L2 and L3shall be in that order. Check with Amprobephase sequence adapter PSA-1 or equivalent.
2.9 CONTROLS
2.9.1 CONNECTIONS
Controls which are to be field installedshould be connected in accordance withthe appropriate wiring diagramaccompanying the unit. The followingconnections should be made whereapplicable:
1.) Connect a set of normally openauxiliary contacts from chilled waterpump contactor into unit controls asshown on unit wiring diagram.
2.) Install a chilled water flow switch(paddle type recommended) (ordifferential pressure switch) in straightlength of chilled water piping to avoidturbulence. Connect in same electricalcircuit as ( 1.)
2.9.2 SETTINGS
All controls are factory set, howeveroperating control settings are not alwaysapplicable under all operating conditions.For recommended control settings, seewiring diagram accompanying unit. Safetycontrols must be set to factoryrecommendations.
2.10 REQUEST FOR START-UP REPRESENTATIVE
After the installation has been completed and
checked, Form 9180 must be filled out and sent tothe Dunham-Bush Service Department forauthorized start-up representative to perform the
initial start-up of the Dunham-Bush packagedchiller. The purchaser will have competentservice and operating personnel in attendance to
assist in the work involved, and also to be trainedin the service and maintenance of this unit.(During the warranty period, the manufacturer is
responsible for parts only upon proof of defectiveworkmanship or manufacture).
Following receipt of the signed Form 9180, a
representative will be sent to the customer. Hewill inspect the installation to determine whether
it meets Dunham-Bush requirements; perform theinitial start-up of the installation; determinewhether it is in satisfactory operating condition;
and instruct the specified customer personnel inits operation and maintenance for the length oftime specified in the purchase contract.
NOTE: Sump oil heaters should be energized fora minimum of 24 hours and the oil sumptemperature must be at a minimum of
100°F (38°C) prior to arrival of start-uprepresentative. This will ensure that theoil is warm enough to vaporize any
dissolved refrigerant and that the oil iswithin the normal operating temperaturerange.
WARNING: The compressor(s) should bestarted initially ONLY under thedirect supervision of an
Authorized Dunham-Bush Start-Up Representative.
3.0 OPERATION
3.1 GENERALThe unit should be started up only by arefrigeration technician who is familiar withaccepted operation practices for refrigerationsystems.Use small screw unit start-up report to record alltemperature, pressure, electrical readings andcontrol settings. A copy must be forwarded toDunham-Bush, before the warranty will behonored.
3.2 UNIT PIPINGEach unit has a separate refrigerant circuit foreach compressor. See Figure 3.2 for typical unitpiping schematic.
3.3 SYSTEM WATER FLOWRATE
The quantity of chilled water being circulated canbe measured quite accurately (±5%) bydetermining the water pressure drop through thecooler and reading GPM from the cooler pressuredrop curve, Figure 3.3. Connect reliable pressuregauges to valves installed in cooler entering andleaving water vent connections and read pressuredifference with chilled water pump in operation.An alternative method of determining GPM is tomeasure pressure difference from pump inlet tooutlet and read GPM from pump curve.However due to the quality of water at the jobsite,the accuracy of the curve might vary. Conditionssuch as water hardness, organic material,suspended solids and water velocity maycontribute to a greater fouling. The quality of thewater could be maintained by chemical treatmentand periodical cleaning. The curve plotted isbased on a clean water system.
3.4 STANDARD AMBIENTUNIT OPERATION (65°FMINIMUM AMBIENT)INCLUDING OVERNIGHTSHUT-DOWN ANDMORNING RESTART
Caution: These units may be equipped withmanifold installed manual discharge valve thatmust be opened before attempting to start.
Important: Do not use chilled water pumpoperation via the flow switch or Aux chilledwater pump contacts to start & stop this unit.These are safety controls, not operationalcontrols.
3.4.1 AIR COOLED PACKAGECHILLER START-UP
The unit is ready for start-up when thefollowing procedures have beencompleted.
1. Water piping for the cooler is installedand tested.
2. Electrical connections are made andproperly fused.
3. Unit has been leak tested. leakscorrected, and charge completed.
4. Compressor crankcase heater(s) hasbeen energized for a minimum of 24hours.
5. Calibrated refrigerant gages have beenconnected to the suction and discharge.
6. Turn on the chilled water pump, checkdirection of rotation and adjust thewater flow through the cooler to thespecified flow rate. Bleed off allentrained air.
7. Manually energize the fan starters andcheck the fan rotation. Fans should pullair through the condenser coil anddischarge vertically upwards.
8. Check all refrigerant valves to be surethey are open.
9. Proceed to System Start-up.
Compressor #1 will start in about 15minutes & proceed to load up if leavingwater temperature is above setpoint.Compressor #2 will follow as the demanddictates.
3.5 SYSTEM START UP1. Before starting the compressor(s), check all
three phases of supply voltage, of all legs ofthe motor. They must be within ±10% of thenameplate voltage. Check to be surecompressor is not running backwards.
3.0 OPERATION
FIGURE 3.2 TYPICAL PIPING SCHEMATIC
A.) 2 COMPRESSORS
3.0 OPERATION
B.) 3 COMPRESSORS
1
10
100
10 100 1000 10000
CHILLED WATER FLOW RATE - USGPM
PR
ES
SU
RE
DR
OP
- F
T W
G
3.0 OPERATION
FIGURE 3.3 COOLER WATER PRESSURE DROP
ACFX 200-6
ACFX 220-6
ACFX 250-6ACFX 280-6ACFX 300-6
ACFX 330-6
ACFX 360-6
ACFX 420-6
ACFX 450-6
ACFX 480-6
ACFX 500-6
ACFX 530-6
3.0 OPERATION
2. Start compressor(s), check the gages and noteif the pressures are within the prescribedlimits.
3. Stage unit down until all compressors are offand check the compressor crankcase sightglass for oil level. It should be 1/2 to 3/4 of thecompressor sight glass.
4. The electrical control settings should bechecked and if necessary, reset to thosesettings indicated on the wiring diagram.Safety controls are factory set and must bemaintained at settings indicated on the wiringdiagram.
5. The temperatures of the chilled water both inand out, should be checked to insure the unit isoperating within the desired temperatures.
3.6 SHUT-DOWN (OVERNIGHTOR WEEKEND)
To shut-down in the unit with compressors on oroff, turn each individual compressor switch. Donot close any valves. The chilled water pump maythen be turn off. If it is possible that the overnightambient will drop below 45ºF, it is preferable toleave the chilled water pump on. Finally, do notopen the main unit disconnect. Main power isrequired to keep the sump heaters.
3.7 SEASONAL SHUT-DOWNPROCEDURE
Standard Ambient Units
1. Follow standard overnight shut-downprocedure
2. Turn off chilled water pump
3. Close manual discharge valve
4. Close liquid valve on sealpot
5. If ambient temperature during the extendedshut-down period will not get below freezing,the chilled water system may be left filled, Ifthe ambient temperature will be belowfreezing, drain all water thoroughly, removing
all vent & drain plugs from both heads of thecooler, and blow out tubes will compressed airto avoid serious stagnant water corrosion.
6. Finally, it is recommended that an oil samplebe taken from each compressor & submittedfor lab analysis. Dunham-Bush offers thisservice in its "Oil Kare" program. Thisanalysis should be done at the end of eachoperating season or every 6 months if the unitis used year round, to maintain compressorwarranty.
The power supply to the unit may be de-energized to conserve energy. Just rememberthat all heaters will now be inactive, and thecooler could freeze-up if not properly drained.
3.8 SEASONAL START-UPPROCEDURE
l. Check fan drives for wear, rust, propellerclearance, etc. and make necessary repairs &adjustments. Grease main fan shaft bearingswith a good grade of EP ball bearing grease.
2. Check & clean condenser fin surface ifnecessary. Use a warm water soap solution,being careful not to bend fins. Comb out bentfin areas.
3. Check all power supply connections at allpoints, and all control terminal screws fortightness.
4. Energize main power to unit & leave on for atleast 24 hours in order for compressors tothoroughly warm up.
5. Start chilled water pump and verify correctflow-rate, glycol % if required. Bleed-offsystem air if necessary.
6. Open main discharge valve in dischargeheader.
7. Open liquid valve on sealpot.
8. Turn control circuit power switch on, and allindividual compressor circuit switches. Presscomputer keyboard reset key (RST).Compressors should start after start-up clocktimes out and will come on in sequence tosatisfy the existing load.
3.0 OPERATION
3.9 SAFETY RELIEF VALVESEach pressure vessel is protected by a safety reliefvalve as required by ASME Code. Eachcompressor is protected by a relief valve which isvented to atmosphere. Never install any kind ofshut-off valve in a safety relief vent line.
3.10 REFRIGERATION CYCLE-MULTIPLE COMPRESSORACFX
Following is the normal sequence of operation fora unit installed in a typical air conditioningsystem. Refer to Figure 3.2, the typical pipingschematic for multiple compressor ACFX unit.Each vertical screw compressor discharges hot,high pressure gas through service valve or stopvalve and then flow into air cooled, condenserwhere it condenses, rejecting heat to the outdoorair drawn through the coil by fans. The liquidrefrigerant from the condenser drains out from thebottom of the condenser into the economizer feedline.
The refrigerant flows through the economizerfeed ball valve, dropping its pressure, causing itto flash. It then flows into the flash economizertank which is at an intermediate pressure betweencondenser and evaporator Liquid is centrifugallyseparated from the flash gas and the liquid drainsto the bottom of the tank, exits via the economizerdrain line, and passes through the economizerdrain ball valve. Both economizer ball valves areactuated by a Modutrol motor that adjusts flow tomaintain an appropriate refrigerant level in theevaporator, determined by a liquid level floatswitch.
From the drain line, liquid refrigerant flows intothe flooded evaporator, where it boils, cooling thewater flowing inside evaporator tubes. Vaporfrom the boiling refrigerant flows up the suctionpipes through a shut-off valve, suction checkvalve and suction filter (inside compressor) intothe compressor where it is compressed and startsthe cycle again.
Vapor flows from the top of flash economizerinto the compressor at the vapor injection port,
which feeds it into the compressor part waythrough the compression process. Check valveprevents backflow at shutdown in multi-compressor units.
3.11 FAN CYCLINGOn start-up, all fan will remain off (some unitsmay have base fans which run together withcompressor). As the head pressure builds up, nextfan stage will start. Subsequently fan stage willstart if the head pressure continues to rise. Referwiring circuit diagram for number of fan stage.
3.12 LIQUID INJECTIONEach compressor is fitted with a liquid injectionsystem designed to feed refrigerant liquid into thecompressor to provide additional motor coolingas required. The liquid injection is activated bysolenoid valve to hold the compressor dischargegas temperature below 170ºF, the maximumdischarge operating temperature of thesecompressors.
3.13 HYDRAULIC CAPACITYCONTROL SYSTEM
Each compressor has a hydraulic control systemto supply the proper force necessary to actuate thecapacity control slide valve, thereby regulatingcompressor loading for maximum unit capacity. Itis composed of a normally closed valve (A), anormally open solenoid valve (B), an internalpressure regulating valve, with valves A and Bboth energized (A open, B closed) during normalcompressor operation, high pressure oil isdirected to the slide valve. This pressure acts onthe surface of the slide valve piston creating aforce which is sufficient to overcome theopposing spring force and to move the valve inthe direction of increasing capacity. When thecompressor is given a "hold" command, valve Ais de-energized (closed) and slide valve holds itsposition.
NORMALLYOPEN
UNLOADINGSOLENOID
SUCTION
SOLENOIDLOADING
NORMALLYCLOSED
SCHRAEDER VALVE
CHECK
SERVICESUCTION
VALVE
'B'
'A'
VALVE
BOXTERMINAL
3.0 OPERATION
The internal pressure regulating valve allows oilto bleed from the slide valve chamber during thehold condition. If valve B is then de-energized(open), the high pressure oil acting on the slidevalve will be vented to suction, and the pressurein the slide valve chamber will be reduced. The
slide valve spring will now move the slide valveback toward the minimum capacity position.
Under standard conditions, the compressors willload in 60 seconds and unload in 55 seconds.
SLIDE VALVE POSITION
UNLOADING LOADING HOLD
SOLENOID VALVE A(NORMALLY CLOSED)
CLOSED(DE-ENERGIZED)
OPEN(ENERGIZED)
CLOSED(DE-ENERGIZED)
SOLENOID VALVE B(NORMALLY OPENED)
OPEN(DE-ENERGIZED)
CLOSED(ENERGIZED)
CLOSED(ENERGIZED)
FIGURE 3.13 COMPRESSOR CAPACITY CONTROL DETAIL
4.0 ELECTRICAL
4.1 ELECTRICAL DATACOMPRESSOR COND. FAN MTR UNIT DATA USE VOLTAGE
LRAMODEL COMP.MSC
NO'S RLA
1st STEP XLNO'S FLA FLA MCA MFS MIN MAX
1210 1 154 398 995 6 3.6200-6
1210 1 158 398 995 6 3.6355 394 550 414 506
1212 1 189 448 1050 8 3.6220-6
1210 1 158 398 995 6 3.6397 445 600 414 506
1212 1 189 448 1050 8 3.6250-6
1212 1 191 448 1050 8 3.6438 485 600 414 506
1215 1 223 520 1330 8 3.6280-6
1212 1 190 448 1050 8 3.6471 526 700 414 506
1215 1 228 520 1330 8 3.6300-6
1215 1 223 520 1330 8 3.6509 566 800 414 506
1218 1 279 600 1530 9 3.6330-6
1215 1 227 520 1330 9 3.6571 641 900 414 506
1218 1 279 600 1530 9 3.6360-6
1218 1 286 600 1530 9 3.6630 700 900 414 506
1212 1 188 448 1050 6 4.3
1215 1 223 520 1330 6 4.3420-6
1215 1 223 520 1330 6 4.3
711 758 1000 414 506
1215 1 223 520 1330 6 4.3
1215 1 223 520 1330 6 4.3450-6
1215 1 223 520 1330 6 4.3
746 802 1000 414 506
1215 1 223 520 1330 6 4.3
1215 1 223 520 1330 6 4.3480-6
1218 1 282 600 1530 6 5.7
814 870 1100 414 506
1215 1 223 520 1330 6 4.3
1218 1 282 600 1530 6 5.7500-6
1218 1 282 600 1530 6 5.7
881 937 1100 414 506
1218 1 282 600 1530 6 5.7
1218 1 282 600 1530 6 5.7530-6
1218 1 282 600 1530 6 5.7
949 1019 1250 414 506
NOTES: 1. RLA IS RATED LOAD AMPS.2. LRA IS LOCK ROTOR AMPS.3. XL IS ACROSS THE LINE STARTING.
4. FLA IS FULL LOAD AMPS.5. MCA IS MINIMUM CIRCUIT AMPACITY.6. MFS IS MAXIMUM FUSE SIZE.
4.2 WIRING DIAGRAMFigure 4.2 are typical wiring diagrams for a 2-compressor unit. This may not be an accuraterepresentation of your unit. It is best to use thewiring diagram mounted in the package controlpanel. A copy of that diagram is furnished withthe unit owner’s manual.
4.3 TYPICAL OPERATIONThe Dunham-Bush rotary screw air-cooled waterchiller depends mainly on its on-boardmicrocomputer for control. Operation described isfor a two-compressor units and is very similar forsingle and three compressor units.
For initial start-up, the following conditions mustbe met:
] Power supply to unit energized.
] Unit circuit breakers in the "on" position.
] Control power switch on for at least 15minutes. Compressor switches on.
] Reset pressed on microcomputer keypad.
] Chilled water pump running and chilled waterflow switch made.
] Leaving chilled water temperature at least 2°Fabove setpoint.
] All safety conditions satisfied.
4.0 ELECTRICAL
After all above conditions are met, themicrocomputer will call for the lead compressorto start. After a one-minute delay, the firstcontactor (e.g. 1M-1) is energized followed by thesecond contactor (e.g. 1M-2) after one-second-time delay. This provides reduced inrush steppedstart. The compressor 15-minute anti-recycletimer is initiated at compressor start.
When the compressor starts, the microcomputermonitors amperage by means of 1CT, voltageusing 3T, leaving water temperature using TS,and condensing pressure. These inputs are used tocontrol the loading and staging of the compressor.The compressor's loading is controlled by pulsingsignals to the load and unload solenoids.
The compressor and cooling capacity iscontrolled by pulsed signals to load and unloadsolenoid valves on the compressor. When thecompressor starts, it is fully unloaded, yieldingabout 25% of its full load capacity. As thecomputer gives it load signals, capacity graduallyincreases. The rate of compressor loading isgoverned by ramp control which is adjustable inthe computer.
The computer responds to leaving chilled watertemperature and its rate of change which isproportional and derivative control. If leavingchilled water temperature is within the deadband(+/-0.8°F from setpoint), no load or unloadcommands are given. If chilled water temperatureis above deadband, the computer will continueloading the compressor until a satisfactory rate ofdeclined is observed. If leaving chilled watertemperature is below the deadband, thecompressor is commanded to unload. Thus thecompressor capacity is continuously modulated tomatch applied load and hold leaving chilled watertemperature at setpoint.
Condenser control is by fans, of which some arebase fans that are activated upon compressorstarting. The base fans are normally the oneslocated at the liquid line header side of each ‘V’coil. The remaining fans are controlled accordingto discharge pressure and fan stage setpoints bythe microcomputer. Optional low ambient unitsmay have base fan variable speed control which isindependent of the microcomputer, or coilsolenoid control to disable ‘V’ coil sections andfans under the control of the microcomputer.
If the applied load is greater than one compressorcan handle, it will load fully and then themicrocomputer will call for a second compressor.After one minute, the second compressor willstart in the same manner as the first. Then bothcompressors will be commanded to adjust load to50%. They are gradually loaded up together untilthe applied load is satisfied. In this way the twocompressors share the load equally.
If the applied load decreases to the point that bothcompressors are running at about 40% capacity,the computer shuts down the lag compressor andloads the remaining compressor to about 80%. Ifapplied load decreases further, the remainingcompressor unloads proportionately. If appliedload decreases to less than the minimum capacityof one compressor, the leaving chilled watertemperature will decline to 2°F below setpoint, atwhich time the lead compressor will shut down. Itwill restart automatically if leaving chilled watertemperature rises to 2°F above setpoint and both15 minute anti-recycle and one minute start delaytimers are satisfied.
During start-up operation, the computer monitorsthe difference between discharge and suctionpressures to insure that minimum of 30 psidifferential is available for compressorlubrication. If the difference falls below aminimum of 30 psi, the computer closesrefrigerant flow control valves, starving theevaporator, causing evaporator pressure to drop,increasing differential pressure. This is especiallyhelpful at startup, when warm chilled water andlow ambient temperature would cause a low headsituation. This feature is called EPCAS:Evaporator Pressure Control at Startup. It is oneof several proactive control features of themicrocomputer which overcome potentialproblems while continuing operation.
Two additional proactive features are low suctionand high discharge pressure override. If operatingpressures approach trip level, compressors areunloaded as necessary to continue operation.
To shut down the unit automatically, the customercontrol contacts must be opened. To shut downthe unit manually, simply shut off the compressorswitches. This will cause a no-run alarm that mustbe reset to restart the compressor.
4.0 ELECTRICAL
FIGURE 4.2 TYPICAL WIRING SCHEMATIC
4.0 ELECTRICAL
Ω
Ω
8
8
5ΡΕΣ
Σ5
Σ4
∼∼
270
270
4.0 ELECTRICAL
4.0 ELECTRICAL
4.0 ELECTRICAL
TABLE 4.2 TYPICAL CONTROL DATA SHEET
4.4 MICROCOMPUTERCONTROLLER
This unit is controlled by a microcomputercontrol system. The system is composed of fourmicrocomputer boards, a display board andanalog and digital sensors. The following sectionsdescribe the system and how to operate it.
The display board has a 20-key keypad and a 2 x40 LCD display. The keypad and display can beused to determine the status of the compressor,and refrigeration system. Various setpoints canalso be displayed and altered.
The status of the machine can also be monitoredby a computer terminal either locally or remotelyby a modem. The terminal must be able to handleRS232 communications. For more information,Please contact Dunham-Bush Industries, M & EService Department.
4.4.1 TO DISPLAY DATA FROM THEMENU1. Press the MENU key.
2. Use the up or down arrow keys to selectthe type of information desired. Themain menu items are:DATE & TIME SETCONTROL POINTSANALOG SENSORSDIGITAL SENSORSSETPOINTS A & BALARMSAUTHORIZATION
3. Press the ENTER key.4. Use the up or down arrow keys to select
the desired data. For control points,additional data such as compressoroperating hours and number of startscan be viewed with the right and leftarrow keys.
NOTE: When displaying analog sensors, thePAGE MODE key can be pressed todisplay two new analog inputs after eacharrow key is pressed. Press PAGEMODE again to return to displaying onenew analog input.
4.0 ELECTRICAL
4.4.2 TO RESET ALL CONTROLPOINTS TO COMPUTERCONTROL
1. Press the RESET key. The display willshow RESET ALL CPs to COMMODE? N Y
2. Press the right arrow key to select Y.
3. Press the ENTER key. The reset willnot be accepted if a lockout controlpoint is active. Resolve the problem andreset again.
4.4.3 TO DISPLAY ALARMS
1. Press the MENU key.
2. Use the up or down arrow to selectALARMS.
3. Press ENTER.
4. The day, time, and alarm code isdisplayed. Alarm 1 is the most recentalarm.
5. Press the down arrow to view previousalarms.
6. Determine identity of alarm from alarmcodes on computer instruction label.
4.4.4 TO BECOME AUTHORIZED
1. Select AUTHORIZATION on the mainmenu. Press ENTER.
2. If the current status shown is VIEW,press the authorization code (64) on thenumber keys.
3. Press ENTER. the current status willchange to PROG (program) if accepted.
4.4.5 TO ALTER SETPOINT DATA
1. You must be authorized and in thePROG mode. See Section 4.4.4.
2. Select SETPOINTS A & B on the mainmenu. Press ENTER.
3. Use the up or down arrow keys to selectthe setpoint to be changed. Press
ENTER. A cursor will flash over thesetpoint A value.
4. a.) If you want to change setpoint A,press in the desired new value andpress ENTER. if the new value iswithin allowable limits, it will bestored in memory. The cursor willthen move to setpoint B.
b.) If you do not want to changesetpoint A, press ENTER.
5. Repeat 4, for Setpoint B.
4.4.6 TO CALIBRATE TEMPERATUREAND PRESSURE SENSORS
1. You must be authorized and in thePROG mode. See Section 4.4.4.
2. Display the analog sensor to becalibrated on the top line of the display.
3. Press ENTER to show ZEROCALIBRATION value.
4. Use an accurate gauge to measure theanalog value when it is stable and neardesign conditions.
5. Determine the revised zero calibrationrequired as follows: Meter Reading - AIDisplay + Zero Calibration = New ZeroCalibration. The new zero calibrationmust be rounded to the nearest wholenumber.
6. Press ENTER to place the cursor on thezero calibration value.
7. Enter the new value from 5. Negativevalues are entered by pressing LOWERFUNCTION +/- before the number.
8. Press ENTER to store the revised zerocalibration.
For example, if a suction pressure gauge shows58 psig and the computer displays 60.3 psig witha zero calibration of -1, then new calibrationwould be 58 - 60.3 + (-1)= -3.3(-3). So the zerocalibration should be changed to -3. Then thecomputer will display 58.3.
4.0 ELECTRICAL
4.4.7 TO SET DATE AND TIME
1. You must be authorized. See Section4.4.4.
2. Select DATE & TIME SET on the mainmenu. Press ENTER to display currentdate and time.
3. Press ENTER key to move cursor toeach date/time item.
4. As each item flashes, use the numberkeys to enter revised data if necessary.
5. Press ENTER to continue. The lastENTER will store the new date andtime.
WARNING: Setting the clock will cause asystem reset. The entire unit will shutdown and start over again. If the changewas started inadvertently, press MENUkey before completing the change.
4.4.8 TO DISPLAY DATA WITHOUTACCESSING MENU
1. Press LOWER FUNCTION.2. Press function desired (blue sub-script)3. Press item number to be displayed.
4. Press ENTER.EX: To display analog input #5, pressLOWER FUNCTION, ANALOG INPUT,5, ENTER.
4.4.9 UNIT SCHEDULE OFOPERATIONIf a seven day time schedule of unitoperation is desired, the internal real timeclock of the microcomputer can be used.When the SCHEDULE control point isON, the compressor is allowed to operate.The following procedure is used to modifythe operating schedule.
1. Perform the authorization procedure(See Section 4.4.4).
2. Press MENU key.3. Use Up and Down to select
CONTROL POINTS.
4. Press ENTER.5. Use Up and Down to select
SCHEDULE control point.
6. Use ® to display the first schedule.The standard display screen wouldshow:CP 17 SCHEDULE GRP: 1 SCH: 10000 2400 DAYS: *** ALL DAYS***.This indicates that control point 17named SCHEDULE is controlled byschedule group (GRP) #1. The firstschedule (SCH:1) turns on at 0000hours and off at 2400 hours (militarytime) every day of the week. Thus it ison all the time.
7. To change this schedule, pressENTER. The cursor will flash over theturn-on time.
8. Use the number keys (0-9) to enter therevised turn on time using militaryformat.
9. Press ENTER. The cursor will moveover to the turn-off time.
10. Use the number keys to enter the turn-off time in military format.
11. Press ENTER. The cursor will moveto DAYS during which this scheduleis active.
12. To change the days for this schedule,press one or more of the followingnumber keys: 0- Clear all current days;1- Sunday(S); 2- Monday(M); 3-Tuesday(T); 4- Wednesday(W); 5-Thursday(R); 6- Friday(F); 7-Saturday(A); 8- *** ALL DAYS***.
13. Press ENTER. The revised schedulenumber is now stored.
14. To add another schedule, press theright arrow key and repeat steps 7-13.
15. To delete a schedule, clear all of thedays by pressing 0 at Step 12.The schedule group turns on when anyof the individual schedules turns on.The turn on time does not have to beearlier than the turn off time.Schedules turn on by time and day, butturn off by time alone. For example, aschedule from 1900 to 0700 Saturdayswould turn on at 7:00 PM Saturday(time and day) and turn off at 7:00AM Sunday (time only).
4.0 ELECTRICAL
EXAMPLE: If a unit is to operate at alltimes except between the hours of 1:00AM and 6:00 AM, the followingschedules would be entered:CP 17 SCHEDULE GRP :1 SCH:
1 0000 0100 DAYS:*** ALL DAYS ***CP 17 SCHEDULE GRP:1 SCH:
2 0600 2400 DAYS: ***ALL DAYS ***ANOTHER EXAMPLE: A typicalbuilding may require cooling from 6:00AM to 7:00 PM Monday - Friday andfrom 7:00 AM- 3:00 PM on Saturdays.The schedules would be entered asfollows:CP 17 SCHEDULE GRP:1 SCH:1 0600 1900 DAYS: MTWRFCP 17 SCHEDULE GRP: 1 SCH:2 0700 1500 DAYS: A
4.5 CONTROL FUNCTIONS
4.5.1 Chilled Water Pump interlockAnd Flow Switch (CWP AndCWFS)These are field installed switches, both ofwhich are used to ensure chilled waterflow before the unit is allowed to start.Failure of either one during operation willcause the compressor to shut down.A water flow alarm will be generated andRESET must be pressed to clear thealarm.
NOTE: The flow switch or pump interlock cannotbe used for normal control of the unit.(See Section 4.5.2).
4.5.2 Customer Control interlockControl contacts from an externalcontroller can be used to enable or disableoperation of the unit. The wiring diagramspecifies the terminals to which thecontacts must be wired. To enable theunit, the contacts must be closed. Todisable the unit, the contacts must beopened.
4.5.3 Anti-Recycle Timer(Microcomputer)The compressor motor requires an anti-recycle time delay which prevents restartfor 15 minutes after a start. The purposeof this feature is to avoid frequent startswhich tend to elevate the motor windingtemperature and impose undue wear oncontactors. The microcomputer will notrestart the compressor motor until the 15minutes have elapsed. COFF is displayedwhen the compressor control point (1 CPfor compressor 1 respectively) isaddressed, and when other conditions forcompressor start are satisfied. See Section4.3.
4.5.4 Load Control (Microcomputer)The microcomputer controls the leavingwater temperature within a narrowdeadband by pulsing load and/ or unloadsolenoids on the compressor. The loadand unload solenoids position the slidevalve within the compressor to control itscapacity. The microcomputer determinesa desired level of loading and varies pulseduration depending on difference betweenload target and actual load. The loadtarget is varied based on rate of approachto desired temperature preventingsignificant temperature oscillations. Thecurrent limit function (see Section 4.5.7)overrides the temperature control.The status of the compressor can beobserved by displaying the compressorcontrol point (1CP). One of the followingmessages will be displayed:
COMP # LOAD Automatic loadCOMP # HOLD Automatic holdCOMP # UNLD Automatic unloadCOMP # OFF Off on temperature or
customer controlCOMP # COFF Off on timer (C lock
off)COMP # LOFF Manual off or safety
shutdownWhere # is 1 for compressors 1respectively.
4.0 ELECTRICAL
4.5.5 Ramp Control (Microcomputer)Another feature of the microcomputer isramp control, which is the ability to varyload time of the machine from start. Oftenwhen the machine is started, the water inthe chilled water circuit is warm, and theunit will go to full load quickly. Withramp control, the user can program thecomputer so that it loads at apredetermined rate. This is a valuabletool, since it can help reduce powerconsumption and demand charges. Twovariables are used to define the ramp
profile: Ramp rate and start point. Ramprate defines the length of time the unittakes to load from start point to full load.Start point is the percent of full load atwhich the ramp begins. The ramp rate Asetpoint can be set anywhere from 0.1 to0.4, smaller values producing slowerloading rates. The ramp start B setpointcan be set anywhere between 10 and50%. The compressor will load quickly tothis value and then follow the ramp slopefrom there. See Table 4.5.5 for ramp ratesat various settings.
TABLE 4.5.5 SAMPLE RAMP TIMES (MINUTES)
A.) TWO-COMPRESSORS UNIT
Ramp RateSetpoint
0% Start PointSetpoint
50% Start PointSetpoint
75% Start PointSetpoint
0.1 33.4 25.0 20.9
0.2 16.6 12.5 10.4
0.3 11.2 8.4 7.0
0.4 8.4 6.3 5.2
0.5 6.6 5.0 4.1
0.6 5.6 4.2 3.5
0.8 4.2 3.1 2.6
1.0 3.4 2.5 2.1
B.) THREE COMPRESSORS UNIT
Ramp RateSetpoint
0% Start PointSetpoint
50% Start PointSetpoint
75% Start PointSetpoint
0.1 100.0 83.3 75.0
0.2 50.0 41.7 37.5
0.3 33.3 27.8 25.0
0.4 25.0 20.8 18.8
0.5 20.0 16.7 15.0
0.6 16.7 13.9 12.5
0.8 12.5 10.4 9.4
1.0 10.0 8.3 7.5
C.) FOUR-COMPRESSORS UNIT
Ramp RateSetpoint
0% Start PointSetpoint
50% Start PointSetpoint
75% Start PointSetpoint
0.1 133.3 116.7 108.3
0.2 66.7 58.3 54.2
0.3 44.4 38.9 36.1
0.4 33.3 29.2 27.1
0.5 26.7 23.3 21.7
0.6 22.2 19.5 18.0
0.8 16.7 14.6 13.5
1.0 13.3 11.7 10.8
4.0 ELECTRICAL
4.5.6 Current Limiting (Microcomputer)
A maximum desired current is specifiedby amp limit B setpoint for eachcompressor. Above the B setpoint, thecompressor will not load. If the amps riseabove the A setpoint, the computer willgive an unload command to thecompressor until the current drops belowthe A setpoint. The amp value in the Asetpoint should be 10% of RLA higherthan the B setpoint.
4.5.7 Staging Control (Microcomputer)On multiple-compressor machines, whenthe microcomputer determines that acompressor is fully loaded andtemperature is not being maintained,another compressor is added. Whenunloading, a compressor is taken off linewhen the computer determines that theremaining compressors can control watertemperature.
4.5.8 Manual Lead-Lag Control(Microcomputer)On multi-compressor machines, the leadcompressor can be chosen by storing 0.0or 1.0 in the lead setpoint B position. 0.0is for lead on compressor #1, and 1.0 isfor lead on compressor #2 (if applicable).
4.5.9 Manual Load-Unload Control(Microcomputer)Loading of the compressor can becontrolled manually. To place computerin manual control, do the following:
1. Press RESET if the compressor islocked out.
2. Obtain authorization per 4.4.4.
3. Select CONTROL POINTS on themain Menu. Press ENTER.
4. Use up or down arrow to select thecompressor to be controlled manually.Press ENTER.
5. Press up or down arrow to select MAN
ON. Press ENTER. The compressorwill start and operate on manualcontrol.
6. Use the following keys to control thestatus of the compressor:
1 - Hold
2 - Load
3 - Unload
Manual control is maintained for 15minutes after the last manual entry. Afterthis, the compressor reverts to automaticcontrol. To retain manual control, enter a1, 2, or 3 command to the compressor atleast once every 15 minutes. (See Item 5above)
In manual control, to transfer from onecompressor to another or to display data,press MENU, then continue as above.
CAUTION: Do not start compressormanually more than once every 15minutes. Verify that chilled water flowswitch is closed.
4.5.10 Chilled Water Reset andCustomer Control Interlock(Optional)
The chilled water temperature setpointcan be raised automatically by a 0-5 VDCsignal provided by an external controller.The reset signal must be between 0VDCand 5VDC, with 0VDC being no resetand 5VDC being max. reset. Themaximum temperature reset (increase)desired must be stored in CWR max. Bsetpoint. For example, to raise the chilledwater setpoint from 44°F to 50°F (6.0°F)with a 5VDC input, a 6.0 is stored inCWR max. setpoint.
Control contacts from an externalcontroller can be used enable or disableoperation of compressors. The wiringdiagram specifies the terminals to whichthe contacts must to be wired. To enablethe compressors, the contacts must heclosed. To disable the compressors, thecontacts must be opened.
4.0 ELECTRICAL
4.5.11 Variable Fan Speed Control(Optional)When variable fan speed control has beenapplied with the package, an output fromthe computer controls the Variable SpeedDrive (VFD). The VFD is turned on tomaintain the set discharge pressure. Fanspeed increases as discharge pressurerises and decreases as discharge pressuredrop. Refer VFD manual for driveoperation.
4.5.12 Sump Heater ControlEach compressor is fitted with an oilsump band-heater. The heater isenergized at all times when compressor isoff and de-energized when thecompressor is running.
Its purpose is to prevent refrigerantmigration into the oil during shut down.For this reason, it is essential that heatersbe energized for 24 hours before startinga compressor.
4.6 SAFETY FUNCTlONS
4.6.1 Control Power Loss(Microcomputer)
The microcomputer can be set up to startautomatically or manually after a powerfailure to the microcomputer. The powerloss B setpoint is factory set to 0.0 toallow automatic start after a controlpower loss. To select manual reset, setpower loss B setpoint to 1.0. In this case,a power loss alarm will be stored by themicrocomputer and RESET must bepressed to start.
4.6.2 Low Pressure Cut-off(Microcomputer)
This function protects the unit fromoperating at abnormally low evaporatorrefrigerant pressure. The microcomputerwill shut down the compressor whencooler pressure falls below the low
pressure setpoint and turn on the alarmpilot light.
A low pressure alarm will be recorded bythe microcomputer. Reset by pressing theRESET button on the microcomputer.Standard setpoint is 45 psig for watersystems.
4.6.3 Evaporator Freeze Shutoff(Microcomputer)
If the leaving chilled water temperaturedrops below the freeze setpoint, themicrocomputer will shut down the unitand store the freeze alarm. After solvingthe problem, press RESET on themicrocomputer to clear the alarm.
4.6.4 High Pressure Cut-off(Microcomputer)
This function protects the compressorfrom operating at abnormally highdischarge refrigerant pressures. Themicrocomputer will shut down thecompressor when condenser pressurereaches the high pressure set-point, andturn on the alarm indicator lamp on thecontrol box. The high discharge pressurealarm will be recorded by the micro-computer. Reset by pressing the RESETbutton on the microcomputer. Setpoint is360 psig.
4.6.5 Oil Level Sensor (LS)An oil level sensor is located in eachcompressor. If low oil indication (digitalinput is OFF) persists for 60 secondsduring compressor operation, themicrocomputer will then shut down thecompressor. The status of the level sensorcan be seen on the computer display orthe associated LED of the Digital I/OBoard. Failure is indicated on the alarmpilot light. The low oil alarm code will berecorded by the computer. Press theRESET key to reset the system. SeeSection 5.8 concerning oil level.
4.0 ELECTRICAL
4.6.6 High Oil TemperatureThermostat (12TAS)A thermostat is located in eachcompressor which will open thecompressor run circuit if oil temperatureexceeds 203°F. The high oil temperaturepilot light will indicate an excessive oiltemperature and a No-Run error will berecorded by the computer. Reset isactivated by pressing the RESET buttonon microcomputer.
4.6.7 Motor Temperature Protector(1 TAS) - OptionalThree thermistor sensors are embedded inthe windings of each compressor motor.They are monitored by a solid state motortemperature protector. If any exceed safetemperature, the protector opens thecompressor run circuit and lights theappropriate "high motor temperature"(HMT) pilot light. The microcomputerthen stores a No-Run error. To reset themotor temperature protector, press theappropriate "HMT RESET" button on thecontrol panel. Hold reset button for 5seconds . Then press RESET button onthe microcomputer.
4.6.8 Overload Protector (OL)A solid state overload protects eachcompressor by three phase currentmonitoring to prevent high current draw.The trip setting is factory set and is resetby pressing button on overload aftercorrecting problem. The RESET buttonon micro-computer must also be pressedto clear the alarm. A no-run error isstored in the microcomputer.
4.6.9 Under Voltage Relay (UVR)The UVR protects the unit from thefollowing electric supply malfunctions:Phase Control Relay, phase reversal andsingle phasing. If the UVR trips, a control
relay (lCR) will de-energize and open thecontrol circuit. A LED light, located onthe PCR, indicates a good voltage supply.The power loss A setpoint is factory set to0.0 to allow automatic start after UVRfailure. Compressor will not start for 15minutes after failure. To select manualreset, set power loss A setpoint to 1.0. Inthis case, a power loss alarm will bestored by the microcomputer and RESETmust be pressed to start.
4.6.10 Sensor Alarm (Microcomputer)If the computer measures an analog value(temperature, pressure, volts.) that is farbeyond normal operating values, theassociated compressors are shutdown.The computer then stores the alarm codecorresponding to the sensor alarm. Asensor alarm indicates a problem in theanalog measurement system.
4.6.11 No-Stop Alarm (Microcomputer)If the microcomputer turns off acompressor, but the compressor digitalinput does not turn off, a No-Stop alarmis generated. The computer will turn offthe control power relay which disables allcompressor control circuits and will turnon the alarm light. This alarm indicates awiring or hardware error.
4.6.12 Low Differential PressureAlarm (Microcomputer)For proper lubrication, a compressorrequires a 30 psi differential pressurebetween condenser and evaporatorpressures. If the differential pressure isless than 30 psi for 3 minutes while acompressor is operating, all compressorswill be shut down. The microcomputerwill store the low differential pressurealarm code and turn on the alarm light.The RESET key must be pressed to clearthe alarm.
5.0 MAINTENANCE
5.1 GENERALAs with all mechanical equipment, a program ofregular inspection, cleaning and preventivemaintenance by trained personnel will contributegreatly to the long satisfactory service life of thisproduct.
5.2 PERIODIC INSPECTIONRead essential temperatures and pressuresperiodically to see that they indicate normaloperation. It is a good idea to record thesereadings on a log sheet. If any abnormal operationis observed, try to remedy it. See TroubleShooting Guide Section.
5.3 MONTHLY INSPECTIONRemote dirt and debris from condenser coil. Shutunit down, open main disconnect, inspect controlpanel, checking for loose wires, burned contacts,signs of overheated wires, etc. Restart unit andcheck performance of controls. Check sightglasses for proper refrigerant charge, seecharging.
5.4 VESSEL MAINTENANCE
5.4.1 GENERALThe efficient performance of the coolerand condenser heat transfer surfaces isessential for efficient performance ofyour packaged water cooling machine. Ifthese surfaces accumulate a film of dirt,scale or slime, their performanceefficiency will degrade substantially. Therefrigerant side of heat transfer surfacesdoes not foul since refrigerant is a goodsolvent and it is in a closed, filtered cycle.Water side surfaces can foul from thewater system. A program of watertreatment can slow the rate of fouling onheat transfer surfaces, but not eliminate it.
5.4.2 WATER SIDE CLEANING OFCOOLER
The effects of fouling of the coolerheattransfer surfaces can be detected byrecording full load performance data onthe log sheet. The best measure ofperformance of cooler is approach, whichis the difference between leaving watertemperature and saturated refrigeranttemperature at the pressure in the vessel.At full load, read cooler pressure andleaving chilled water temperature on thecomputer. Then use Table 5.4.2 to findsaturated temp. in cooler. Then calculateapproaches as follows:
Cooler Approach = T lvg chilled water -T sat cooler
If the approach increases by more than2°F above the approach recorded at cleanconditions, the tubes should be cleaned. Itis generally advisable to clean the waterside surfaces at least annually and moreoften if severely foul water is used. Inchemical cleaning, a caustic solution ispumped through the heat exchanger,which attacks dirt, slime and mineraldeposits and flushes then away.Chemicals can be recommended by watertreatment specialists, but it is important torinse the system thoroughly after cleaningto remove the chemicals before theyattack the metal surfaces.
5.5 AIR COOLEDCONDENSER CLEANING
The face of the condenser should be cleaned atleast once a month during operation. If conditionsare bad and condensers pick up dirt very quickly,it is suggested that they can be cleaned morefrequently. If the condenser is allowed to get toodirty, the unit will run at high head pressure andwill not give satisfactory performance.
5.0 MAINTENANCE
TABLE 5.4.2 R-22 PRESSURE / TEMPERATURE PROPERTIES
Pressure Temperature Pressure Temperature Pressure Temperature
psig kPa oF oC psig kPa oF oC psig kPa oF oC
0 101.4 -41.4 -40.8 104 818.6 61.3 16.3 208 1535.9 104.1 40.1
2 115.2 -36.4 -38.0 106 832.4 62.4 16.9 210 1549.7 104.8 40.4
4 129.0 -31.8 -35.4 108 846.2 63.4 17.4 212 1563.5 105.4 40.8
6 142.8 -27.7 -33.2 110 860.0 64.4 18.0 214 1577.3 106.1 41.2
8 156.6 -23.8 -31.0 112 873.8 65.4 18.6 216 1591.0 106.7 41.5
10 170.3 -20.2 -29.0 114 887.6 66.4 19.1 218 1604.8 107.4 41.9
12 184.1 -16.9 -27.2 116 901.4 67.4 19.7 220 1618.6 108.0 42.2
14 197.9 -13.7 -25.4 118 915.2 68.3 20.2 222 1632.4 108.6 42.6
16 211.7 -10.7 -23.7 120 929.0 69.3 20.7 224 1646.2 109.3 42.9
18 225.5 -7.8 -22.1 122 942.8 70.2 21.2 226 1660.0 109.9 43.3
20 239.3 -5.1 -20.6 124 956.6 71.2 21.8 228 1673.8 110.5 43.6
22 253.1 -2.5 -19.2 126 970.4 72.1 22.3 230 1687.6 111.2 44.0
24 266.9 0.0 -17.8 128 984.1 73.0 22.8 232 1701.4 111.8 44.3
26 280.7 2.4 -16.4 130 997.9 74.0 23.3 234 1715.2 112.4 44.7
28 294.5 4.8 -15.1 132 1011.7 74.9 23.8 236 1729.0 113.0 45.0
30 308.3 7.0 -13.9 134 1025.5 75.8 24.3 238 1742.8 113.6 45.3
32 322.1 9.2 -12.7 136 1039.3 76.6 24.8 240 1756.6 114.2 45.7
34 335.9 11.3 -11.5 138 1053.1 77.5 25.3 242 1770.4 114.8 46.0
36 349.7 13.3 -10.4 140 1066.9 78.4 25.8 244 1784.2 115.4 46.3
38 363.5 15.3 -9.3 142 1080.7 79.3 26.3 246 1797.9 116.0 46.7
40 377.2 17.2 -8.2 144 1094.5 80.1 26.7 248 1811.7 116.6 47.0
42 391.0 19.1 -7.2 146 1108.3 81.0 27.2 250 1825.5 117.2 47.3
44 404.8 20.9 -6.2 148 1122.1 81.8 27.7 254 1853.1 118.3 47.9
46 418.6 22.6 -5.2 150 1135.9 82.6 28.1 258 1880.7 119.5 48.6
48 432.4 24.4 -4.2 152 1149.7 83.4 28.6 262 1908.3 120.6 49.2
50 446.2 26.1 -3.3 154 1163.5 84.3 29.1 266 1935.9 121.8 49.9
52 460.0 27.7 -2.4 156 1177.2 85.1 29.5 270 1963.5 122.9 50.5
54 473.8 29.3 -1.5 158 1191.0 85.9 29.9 274 1991.0 124.0 51.1
56 487.6 30.9 -0.6 160 1204.8 86.7 30.4 278 2018.6 125.1 51.7
58 501.4 32.4 0.2 162 1218.6 87.5 30.8 282 2046.2 126.1 52.3
60 515.2 33.9 1.1 164 1232.4 88.3 31.3 286 2073.8 127.2 52.9
62 529.0 35.4 1.9 166 1246.2 89.0 31.7 290 2101.4 128.3 53.5
64 542.8 36.9 2.7 168 1260.0 89.8 32.1 294 2129.0 129.3 54.1
66 556.6 38.3 3.5 170 1273.8 90.6 32.6 298 2156.6 130.3 54.6
68 570.3 39.7 4.3 172 1287.6 91.3 32.9 302 2184.2 131.4 55.2
70 584.1 41.0 5.0 174 1301.4 92.1 33.4 306 2211.7 132.4 55.8
72 597.9 42.4 5.8 176 1315.2 92.8 33.8 310 2239.3 133.4 56.3
74 611.7 43.7 6.5 178 1329.0 93.6 34.2 314 2266.9 134.4 56.9
76 625.5 45.0 7.2 180 1342.8 94.3 34.6 318 2294.5 135.4 57.4
78 639.3 46.3 7.9 182 1356.6 95.0 35.0 322 2322.1 136.4 58.0
80 653.1 47.5 8.6 184 1370.4 95.8 35.4 326 2349.7 137.3 58.5
82 666.9 48.7 9.3 186 1384.1 96.5 35.8 330 2377.3 138.3 59.1
84 680.7 50.0 10.0 188 1397.9 97.2 36.2 334 2404.8 139.2 59.6
86 694.5 51.2 10.7 190 1411.7 97.9 36.6 338 2432.4 140.2 60.1
88 708.3 52.3 11.3 192 1425.5 98.6 37.0 342 2460.0 141.1 60.6
90 722.1 53.5 11.9 194 1439.3 99.3 37.4 346 2487.6 142.1 61.2
92 735.9 54.6 12.6 196 1453.1 100.0 37.8 350 2515.2 143.0 61.7
94 749.7 55.8 13.2 198 1466.9 100.7 38.2 354 2542.8 143.9 62.2
96 763.5 56.9 13.8 200 1480.7 101.4 38.6 358 2570.4 144.8 62.7
98 777.2 58.0 14.4 202 1494.5 102.1 38.9 362 2597.9 145.7 63.2
100 791.0 59.1 15.1 204 1508.3 102.8 39.3 366 2625.5 146.6 63.7
102 804.8 60.3 15.7 206 1522.1 103.4 39.7 370 2653.1 147.5 64.2
5.0 MAINTENANCE
Dirty coils can be cleaned using a soft brush or byflushing with cool water or commerciallyavailable coil cleaners. DO NOT USE HOTWATER OR STEAM. To do so will causeexcessive pressure in the system. The face of thecondenser should be cleaned at the beginning ofthe season and periodically thereafter ifconditions require.
5.6 ELECTRICALMALFUNCTION
The unit has four devices designed to protectcompressor motors and manual motor controllersfrom electrical malfunctions: Circuit breakers.starter overload relays, under voltage relay, andmotor over temperature protectors (optional).
If the under voltage relay trips, it is a sign oftrouble in incoming power. If it trips again afterresetting, call your electric utility to investigatethe problem. If circuit breaker or motor overloadrelay or motor over temperature protectors trip,this is a sign of possible motor trouble. DO NOTreset and try to run compressor again. Callauthorized service representative to check formotor trouble. Resetting these safety devices andrepeated starting could turn a minor motorproblem into a costly major motor burnout.
5.7 REFRIGERANT CHARGE
All packaged chiller units are given a completecharge of refrigerant at the factory. The type andamount of refrigerant required is in PhysicalSpecifications. The total refrigerant shown is forthe entire system. Since these units have separate
circuits, each circuit should be consideredseparately for charging.
In order to check proper refrigerant charge, lookin each liquid line sight glass with the aid of aflashlight during system operation. At alloperating conditions, the sight glass should beclear. If bubbles are visible at any operatingcondition, the circuit is short of charge.
Be careful not to overcharge the machine.overcharging will result in considerable liquidlogging in the condenser, and excessivecondensing pressure.
To add refrigerant, connect a refrigerant vessel tothe 1/4" back seating port of the suction valve.Purge the air from the tube with refrigerant gasbefore connecting. With the unit running, openthe refrigerant vessel vapor connection slightly. Ifthe refrigerant vessel is warmer than the cooler,refrigerant will more readily flow from the vesselinto the unit.
5.8 OIL CHARGEThe proper oil charge is in the unit as suppliedfrom the factory. Any operating compressorshould show oil return and oil overflow at alltime. If for some reason, a compressor runs lowon oil, a low oil level switch in the compressorwill shut it down before any damage is done. Inthe event of a low oil shutdown, call a D/Bauthorized service agent to correct the problem.DO NOT ADD OIL TO THE SYSTEM.
Note: Only Suniso 4GS oil may be used in thispackage. Use of other oil is not approvedby Dunham-Bush, and will result in poorperformance of the package.
5.0 MAINTENANCE
5.9 TROUBLESHOOTING
SYMPTOM POSSIBLE CAUSE REMEDY
1. Unit will notstart.
a.) Power off.b.) No control power.
c.) Compressor circuitbreakers open.
d.) Phase control relay open.
e.) Flow Switch open.f.) Compressor switch open.g.) Microcomputer shutdown
not reset.
a.) Check main disconnect switch and main line fuses.b.) Check control transformer fusing.c.) Close circuit breakers. If trip, check compressor.
d.) Check for power supply problems (low voltage, phaseimbalance). When corrected, press reset button.
e.) Start pumps, check flow switch.f.) Turn switch on. Check alarm status. Correct problem.g.) Press reset button.
2. Compressoroverload.
a.) Compressor drawing highamps.
a.) Check motor megohms. Reset overloads , run compressoran check amps. Do not exceed RL x 1.25. Call D/Bserviceman.
3. Compressorhums butdoes notstart.
a.) Low voltage.
b.) No power on one phase of3 phase unit.
c.) Faulty starter or contactor.
a.) Check at main entrance and at unit. Consult powercompany if voltage is low and increase wire size to the unitif voltage is normal at main and low at unit. Voltage mustbe within 10% of motor nameplate rating.
b.) Check fuses and wiring.
c.) Check the contacts and time delay on part wind start.4. Compressor
will not startwhen resetbutton ispushed.
Check light:None
a.) Cooling not required.b.) Computer's time delay
active.c.) Undervoltage relay open.d.) Flow switch open.e.) Compressor switch open.f.) Burned out signal light.i.) Wiring problem
a.) Apply load.b.) Wait 15 minutes max.
c.) See 1.( d.) above.d.) See 1.( e.) above.e.) See 1.( f.) above.f.) Check signal light bulbs.i.) Check wiring against drawing.
5. High oiltemperature
a.) Motor windings failing.b.) Insufficient motor cooling.
a.) Check megohms.b.) Open liquid injection valve slightly.
6. High motortemperature
a.) Motor windings failing. a.) Check megohms. Reset by turning compressor switch offand then on.
7. Low suction a.) Inadequate feed to cooler.b.) Inadequate refrigerant
charge.c.) Fouling of water side of
cooler.
d.) Inadequate chilled waterflow.
e.) Too much oil in system.
a.) Check to see that main expansion valve superheat.b.) See information on charging in Section 5.7.
c.) At high load, check cooler approach (See Section 5.4). Ifapproach is more than 2°F above clean valve, fouling isprobably the trouble. Clean tube.
d.) Measure pressure drop across vessel and determine gpmfrom Figure 3.3. If gpm is low, check chilled water pump,valves and strainers.
e.) If all oil level sight glasses are full at all times, remove oiluntil oil level shows at top of glass on a compressor.
8. Highdischargepressure.
a.) Inadequate air flow acrosscondenser
a.) Check condenser fan operation and condenser coil forclogging.
9. Oil low insump.
a.) Low oil level incompressor.
a.) Low oil level in compressor sight glass is acceptable.
10.Low oilshutdown.
a.) Low oil in compressor. a.) See Section 5.8.
11.Freezewarning.
a.) Operating setpoint toolow.
b.) Load changing too rapidly.
a.) Check leaving water setpoint on microcomputer.
b.) Load on package must drop at reasonable rate forautomatic control to work properly.
12. Impropercapacitycontrol.
a.) Ramp rate incorrect. a.) See Section 4.5.5.
5.0 MAINTENANCE
5.10 SAMPLE LOG SHEET SHEET NO. ..............................
DUNHAM-BUSH SCREW COMPRESSOR PACKAGED CHILLER
NAMEPLATE DATA:
UNIT MODEL NO. ....................................................... UNIT NO..................................... VOLTS:............................ Hz...................
UNIT SERIAL NO. ....................................................... COMPRESSOR MODEL NOS.....................................................................
START UP : DATE.......................................... TIME...................................................
DATE
TIME
ELAPSED TIME METERS
COMPRESSORNO.1.
SUCTION PRESSURE 2.
3.
1.
DISCHARGE PRESSURE 2.
3.
1.
DISCHARGE PRESSURE 2.
3.
DISCHARGE SUPERHEAT 1.
(DISC. TEMP.- SAT. DISCH.)* 2.
3.
1.
LIQUID LINE TEMPERATURE 2.
3.
1.
SUBCOOLING 2.
3.
COOLER WATER TEMPERATURE-IN
COOLER WATER TEMPERATURE-OUT
COOLER PRESSURE DROP PSI/INWATER
COOLER WATER FLOW (GPM)
CONDENSER AIR TEMPERATURE-IN(AMBIENT) AC ONLY
ACTUAL VOLTAGE 1.
COMPRESSOR AMPS 2.
3.
FAN AMPS
VOLTS
*USE TABLE 5.4.2 FOR OBTAINING SATURATED TEMPERATURETHIS LOG SHEET IS PROVIDED AS A RECOMMENDATION OF THE READINGS THAT SHOULD BE TAKEN ON A PERIODIC BASIS. THEACTUAL READINGS TAKEN AND THE FREQUENCY WILL DEPEND UPON THE UNITS APPLICATION, HOURS OF USE, ETC. THIS TYPE OFINFORMATION CAN PROVE VERY USEFUL IN PREVENTING AND/ OR SOLVING PROBLEMS THAT MIGHT OCCUR DURING THE LIFE OFTHE UNIT.
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