TAHI THERMOSTATIC MIXER VALVE (1 and 2 outlets) INSTALLATION INSTRUCTIONS

Issue A435036

Methven warrants this product against manufacturing defects and that it is suitable for use under the operating conditions specified in this instruction sheet. For your warranty please refer to www.methven.com or call Customer Service

TESTING AND MAINTENANCE

● The valve must be tested to ensure correct operation at commissioning and thereafter at intervals no greater than 12 months

● For details on maintenance procedures and spare parts please refer to 435035 Tahi Thermostatic Maintenance Guide

New Zealand0800 804 222

Australia1300 638 483

UK 0800 195 1602

A.

TECHNICAL SPECIFICATIONS

Operating PressureSuitable for mains pressure.Min 150kPa, Max 500kPa (Dynamic).

Operating TemperatureMaximum mixed temperature 47˚C

Inlet ConnectionsFemale ¾” BSP / ¾” NPTAll pipework must be thoroughly flushed prior to installation of the system

OPERATING CONDITIONS OF USE Before installation the operating conditions of use must be checked. Table 1 contains details of the necessary conditions of operation.

Operating pressures above 500kPa will require the installation of a pressure reducing valve.

Single Dual

Maximum Static Pressure 1000kPa 1000kPa

Flow pressure (Hot & Cold)

150- 500kPa 150- 500kPa

Hot Supply Temperature 55 - 85 °C 55 - 85 °C

Optimum Hot Supply Temperature

60 - 65 °C 60 - 65 °C

Cold Water Supply Tem-perature

5 – 25 °C 5 – 25 °C

Maximum Allowable Outlet Temperature

46 °C 46 °C

Max Dynamic Pressure Ratio (Hot to Cold OR Cold to Hot)

3.5 : 1 3.5 : 1

Minimum Temperature Differential Between Either Supply and Outlet Temperature

12 °C 12 °C

Installation Type Concealed Concealed

Number of Outlets 1 2

Service Valves Integral Integral

End Connector Specs FEMALE: ¾” BSP / ¾” NPT

FEMALE: ¾” BSP / ¾” NPT

Overal Dimensions(W x H x D)

164mm x 191mm x 145mm

221mm x 191mm x 145mm

Table 1. Operating Conditions of use

* If a water supply is fed by gravity then the supply pressure should be verified to ensure the conditions of use are appropriate for the valve.

NORMAL OPERATING CONDITIONS

● Inlet Dynamic Pressures nominally balanced to within 10% of each other. ● A temperature differential of approximately 50˚C between the hot and

cold inlet temperatures. ● A temperature differential of 15-30˚C between the mixed blend setting

and either supply.

NOTES ● The Tahi thermostatic mixer valve is precision engineered and will give

continuous safe and controlled performance providing it is installed, commissioned and maintained according to the instructions contained in this document.

● The fitting of strainers is recommended as close as is practicable to the water supply inlets of the thermostatic mixing valve. (Recommended maximum mesh aperture of 0.02”).

● For reasons of general safety hot water storage temperature should generally be maintained between 60˚C - 65˚C.

● The factory nominal preset temperature is achieved with inlet conditions of 300 kPa balanced dynamic pressure, cold inlet temp at 15˚C and hot inlet temp at 70˚C. Preset temperature may vary if site conditions differ from these values.

FLOW RATES

0

10

20

30

40

50

Flow

Rat

e (L

/min

)

150 200 250 300 350 400 450 500

Dynamic Pressure (Inlet) kPa

150200250300350400450500

23.927.330.633.736.739.542.244.8

MAX Flow Rate (L/Min)

29.132.836.439.742.945.948.851.5

Dyn

amic

Sup

ply

Pres

sure

(kP

a)

Single Dual

Single Outlet

Dual Outlet

Symptom 1Only hot or cold water

from outlets

Symptom 3Mixed outlet

temperature drift.

Symptom 4Cross feed of hot

water into supply or vice versa.

Symptom 5Maximum mixed outlet temp too high or low.

Check inlet supplies are not reversed.

Check that hot water is reaching

the mixer.

Check that service valves are both

open.

Check if the hot or cold supply has

failed.

Check that operating

conditions have not changed.

Refer symptom 2.

Refer symptom 3&4.

Check strainers around cartridge for

blockage

Check that dynamic pressures are

nominally balanced.

Check cartridge performance.

Replace if necessary

FAULT FINDING FLOWCHART

Check non-return valve function

Check strainers around cartridge

for blockage

Check that service valves are both

open (see B)

45

4510

6 (±

10m

m)

106

(±10

mm

)84

(±10

mm

)

84 (±

10m

m)

Check limit settings(Refer to

commissioning)

Check non-return valve function.

NOTE: 1) VALVE TRAVEL ±40°. DO NOT OVERSTRESS2) VALVE OPEN DIRECTIONS DIFFER ON HOT AND COLD

7

operate.

Check installationdepth is within

manufacturers statedlimits (refer step 1)

Dual Flow Unit Single Flow Unit

All measurements in mm. All measurements in mm.

163

91

40

Hol

e ce

ntre

s at

173.

2

91

57.4 40

221

Hol

e ce

ntre

s at

173.

2

B. Sevice Valve Operation

OPEN

OPEN

CLOSE

A.

CLOSE

Sing

le F

low

Uni

tD

ual F

low

Uni

t

Rough in assembly

Roug

h in

Box

Trim

Kit

Box

Roug

h in

Box

Trim

Kit

Box

Rough in assembly Lever covers

Faceplate

Escutcheon assembly

Depth Adjustor

Dial knob

Dial Capassembly

2 Short Screws2 Long Screws

Dial GuideWooden stick

Lever coversFaceplate

Escutcheon assembly

Depth Adjustor

Dial knob

Dial Capassembly

2 Short Screws2 Long Screws

Dial GuideWooden stick

Remove screw. Do not discard.

A. Rotate temperature stop fully anti-clockwise

B. If temp ≤ 47°C If temp > 47°C

Adjust (see commissioning)

COMMISSIONING -

The Tahi thermostatic mixer valve is factory set to the required temperature. Check the valve after installation to ensure it operates at the correct outlet temperature.

Prior to commissioning the Tahi thermostatic mixing valve check the following:

● The designation of the thermostatic mixing valve matches the application.

● The supply pressures are within the valves operating range.

● The supply temperatures are within the valves operating range.

● Isolating valves (and strainers preferred) are installed.

REMOVE MAXIMUM TEMPERATURE STOP

A. Remove screw. Do not discard.

B. Rotate clockwise until water temp = 38°C

NOTE - Use of supply line or zone strainers is strongly recomended.

1

MOUNT PARALLEL TO WALL LINING

2

P < 1000 kPa/10 bar(Test pressure must not exceed 1000 kPa/10 bar)

CHECK WATERTIGHTNESS

3 FIT WALL LINING AND REMOVE DUST COVER

USE PROVIDED TEMPLATE FOR ACCURATE HOLE DIMENSIONS.

6mm

MAX

6mm MAX

4

Wall lining

Tiles

TRIM FLUSH AND SEAL WITH SILICON

5 CHECK MAX OUTLET TEMPERATURE

6 FIT TRIM COMPONENTS

7 SET WATER TEMP TO 38°C

8 ASSEMBLE DIAL GUIDE AND DIAL

Dialguide

Dial

DOWNWARD ORIENTIATION OF BUTTON CRITICAL

9 ASSEMBLE HEIGHT ADJUSTOR

A. Hold dial hard against faceplate.

B. Wind depth adjustor into dial. Stop when you feel dial starting to push away from the faceplate

Faceplate

Depth adjustor

8mm Allen key

Dial

C. If depth adjustor protrudes past the front face of the dial; Remove the depth adjustor and trim at midpoint (cut in half). Reassemble as per steps 9: A and B

10A. Insert and tighten

screw using 2.5mm Allen key (finger tight only) to fix dial position.

B. Fit cap (force required)

Tip: Insert dot end of cap first

HOLD DIAL TO STOP ROTATION WHILST TIGHTENING.

FIT DIAL CAP

Note: Dot orientation on dial cap is at top (opposite dial button).

1

2TEMPERATURE MUST NOT EXCEED 47°C

ADJUST TEMPERATURE TO DESIRED MAXIMUM.

3 REASSEMBLE MAXIMUM TEMPERATURE STOP

Assemble with faces aligned as shownNote: Do not Rotate cartridge control knob while assembling Maximum temperature stop

Maximum temperature stop

x 2 (long screws)

x 2 (short screws)

x 2 (Allen screws)

VERT

ICA

L

=

=

96-116mmOPTIMUM = 106mm

= =

PARALLEL

MOUNT MIXER BODY IN WALL CAVITY

NOTE - Levers to be inserted from bottom as shown in diagrams A and B

NOTE - Locating feature

Trim

Depth Adjustor

Dial

Maximum temperature stop

Cartridge control knob

Wall lining

Wall lining

A. B.