Fan Coils Units ControlWall mounted, 2x2 and 3x3 cassette fancoil units

MERCA, SRC and WRC

2Apr 21, 2023

Internal use only

SLM 3

orCN_WIR

SRC

CN_DSP

Note: Only one application is function at one time, either wireless or wired

Wiring connection

MERCA

6Apr 21, 2023

Internal use only

The PCB has 4 modes selection via jumper:

Model

Configuration

Operating Modes

M1 2 pipes Cooling or Heating(no Auto mode)

M2 2 pipes + Aux. Htr

Cooling or Heating with Aux. Htr (no Auto mode)

M3 4 pipes with Boiler

Cooling only or Boiler (with Auto mode)

M4 4 pipe + Boiler

Cooling or Heating with Boiler water (no Auto mode)

Mode Selection

7Apr 21, 2023

Internal use only

Last Memory

Options for last memory setting is available by setting of J_LST.

Last setting that memorized:1. Mode and on/off status2. Set Temperature 3. Fan Speed 4. DC & AC Swing5. Flap stop coordinate (for DC swing off mode)

For Default setting, power up is “OFF” mode, temperaturesetting is 24 o C, indoor fan speed is High and swing modeis off.

Setting J_LST

With Last Memory Setting Short

Default Setting Open

8Apr 21, 2023

Internal use only

Valve Jumper

Setting Jumper Valve

Valve control Short

Valveless control Open

Valve/Valveless Control Selection

9Apr 21, 2023

Internal use only

Turn ON/OFF

3 ways to turn on / off the system:1. Via ON/Off triggering - pressing emergency ON/Off button or LCD controller ON/OFF button. Override timer setting2. Via delay timer - Delay timer is to simulate the ON/OFF pressing after the set numbers of hours 3. Via real time ON/OFF timer - When the real time ON timer set time matches the internal real time clock, unit will switch on, similar for OFF time. The timer setting are retained so

that similar switching can occur 24 hours later

Temperature setting allowed in COOL, DRY, and HEAT mode Temperature range is 16 o C to 30 o C

Temperature range and setting

10Apr 21, 2023

Internal use only

FAN_P Jumper

This option applied to Cool, Heat and Auto mode (apply only during thermostat off cycle)

Fan Priority Setting

Setting Jumper FAN_P

User set speed or low fan if auto mode is selected

Short

Fan stop when thermostat cuts off

Open

11Apr 21, 2023

Internal use only

Heat JumperSetting Jumper Heat

Heat mode allow to use Short

Bar Heat mode Open

Bar Heat Mode Setting

This setting is to bar user from using Heat mode

12Apr 21, 2023

Internal use only

....

Sleep Mode

• Only available for COOL & HEAT modes -

• This function will increase (cooling mode) or decrease (heating mode) the set temperature with time

• The option can be set or reset by the LCD or LED controller. Activation of Emergency switch will reset this option

14Apr 21, 2023

Internal use only

H M L H M L

Water ValveOFF

Water ValveOFF

Water ValveON

Water ValveON

Ts

Ts+1.0

ºC

Cool Mode - With Water Valve

Water valve will cut in if the Tr >= Ts + 1 C. Water valve cut out if Tr=<Ts. Thermostat cut in or out is decided every 30 seconds. In this mode, indoor fan will follow jumper FAN_PRIO setting.

If jumper FAN_PRIO is ON:-- For manual fan speed setting, indoor fan will run as per user set speed. - In AUTO FAN, the indoor fan speed will run as follows:

Tr: room T°

Ts: T°set

15Apr 21, 2023

Internal use only

Manual fan speed

Auto fan speed

User set speed

(H/M/L)

User set speed

(H/M/L)

SLo

SLo

Ts

- 1.0 C

- 0.5 C

H

SLo

SLo

Ts - 0.5 C - 1.0 C

+1.0 C

- 0.5 C M

L

+0.5 C

L

M

H

Ts

Cool Mode - Without Water Valve

Fan speed decision is made every 30 seconds.Fan speed will run as the following diagram

16Apr 21, 2023

Internal use only

HL LM H

Water ValveON

Water ValveON

Water ValveOFF

Water ValveOFF

Ts

Ts-1.0

ºC

Ts-2.0

M L

Auxiliary Heater /Boiler OFF

Auxiliary Heater /Boiler ON

Tr: room T°

Ts: T°set

Heat Mode - With Water Valve

Water valve will cut in if the Tr =< Ts - 1 C. Water valve cut out if Tr<=Ts. Thermostat cut in or out is decided every 30 seconds.

If jumper FAN_PRIO is ON:-- For manual fan speed setting, indoor fan will run as per

user set speed. - In AUTO FAN, the indoor fan speed will run as follows:

17Apr 21, 2023

Internal use only

User set speed

(H/M/L) User set speed

(H/M/L)

SLo SLo

Ts

+1.5 C +1.0 C

H

SLo

SLo

Ts

+2.0 C

+1.0 C +1.5 C

M

L

- 1.0 C

L

M

H - 2.0 C

Ts

Manual fan speed

Auto fan speed

Heat Mode - Without Water Valve

Fan speed decision is made every 30 seconds.Fan speed will run as the following diagram

18Apr 21, 2023

Internal use only

Force On (Valve) 2 minuteUser set speed indoor fan.

If Auto fan low fan

Check Tr14ºC < Tr < 47ºC

Check Tc

2 minuteconfirm?

Tc > Tr+3ºC(Water not suitable)

No

(Force valve to ON)

9 minuteelapsed?

Yes(Force valve OFF 9 minutes)

No

Yes

OthersCheck Tc

2 minuteconfirm?

Tc > 30ºC(Water not suitable)

No

(Force valve to ON)

9 minuteelapsed?

Yes(Force valve OFF 9 minutes)

No

Yes

Enter into coolingthermostat cycle

Tc < Tr+2ºC Tc < 29ºC

Pipe Water Temperature Sensor (Indoor Coil Sensor)Cool Mode - With Water valve

Water valve and indoor fan at set fan speed will be forced to cut in minimum 2 minutes irrespective of thermostat cycle during power

on reset / change mode/unit recover from fault

19Apr 21, 2023

Internal use only

Force On 2 minuteIndoor fan force Low fan

Check Tr14ºC < Tr < 47ºC

Check Tc

2 minuteconfirm?

Tc > Tr+3ºC(Indoor fan force super low fan)(Water not suitable)

No

Yes

Enter into coolingthermostat cycle

Tr-2ºC < Tc <Tr+2ºC(Indoor fan force low fan)

Tc < Tr-3ºC(fault terminated,LED stop blinking)

OthersCheck Tc

2 minuteconfirm?

No

Tc < 25ºC(fault terminated,

LED stop blinking)

(fault declared, LED blinking)

Tc > 30ºC(Indoor fan force super low fan)

(Water not suitable)

Yes

26ºC < Tc < 29ºC(Indoor fan force low fan)

(fault declared, LED blinking)

Pipe Water Temperature Sensor (Indoor Coil Sensor)Cool Mode - Without Water valve

Indoor fan is forced to run at low speed for at least 2 minutes

irrespective of thermostat cycle during power on reset / change mode / unit recover from fault

20Apr 21, 2023

Internal use only

Force On (Valve) 2 minuteUser set speed indoor fan.

If Auto fan low fan

Check Tr14ºC < Tr < 47ºC

Check Tc

2 minuteconfirm?

Tc < Tr-3ºC(no auxiliary Heater/booster)(Water not suitable)

No

(Force valve to ON)

9 minuteelapsed?

Yes(Force valve OFF 9 minutes)(Auxiliary Heater/booster can be used)

No

Yes

Enter into heatingthermostat cycle

Tr-2ºC < Tc < Tr+2ºC(Auxiliary Heater/booster can be used)

Tc > Tr+3ºC(no Auxiliary Heater/booster)

Others Check Tc

2 minuteconfirm?

Tc<25ºC(no auxiliary Heater/booster)

(Water not suitable)

No

(Force valve to ON)

9 minuteelapsed?

Yes(Force valve OFF 9 minutes)

(Auxiliary Heater/booster can be used)

No

Yes

26ºC < Tc < 29ºC(Auxiliary Heater/booster can be used)

Tc > 30ºC(no Auxiliary Heater/booster)

Pipe Water Temperature Sensor(Indoor Coil Sensor)Heat Mode - With Water valve

Water valve will be forced to cut in minimum 2 minutes irrespective of thermostat cycle during power on reset / change mode / unit recover from fault

21Apr 21, 2023

Internal use only

Force On 2 minuteIndoor fan force Low fan

Check Tr14ºC < Tr < 47ºC

Check Tc

Withbooster?

No

Yes

Enter into heatingthermostat cycle

Tr-2ºC < Tc < Tr+2ºC(Auxiliary heater/booster can be used)(Indoor fan**)

Tc > Tr+3ºC(no auxiliary heater/booster)(fault terminated, LED stop blinking)

OthersCheck Tc

Tc > 30ºC(no auxiliary heater/booster)

(fault terminated, LED stop blinking)

(fault declared, LED blinking)

Yes

(fault declared, LED blinking)

26ºC < Tc < 29ºC(Indoor fan force low fan)

(Indoor fan**)

Indoor fan**Heater ON user set speed / Low fan if AUTO fan selectedHeater OFF low fan

(Auxiliary heater/booster can be used)(Run user set fan speed )

Yes

2 minuteconfirm?

No(Indoor fan force super low fan)

Withbooster?

2 minuteconfirm?No

(Auxiliary heater/booster can be used)(Run user set fan speed )

Yes

No

(Indoor fan force super low fan)

Tc < Tr-3ºC Tc < 25ºC

Pipe Water Temperature Sensor(Indoor Coil Sensor)Heat Mode - Without Water valve

Indoor fan is forced to run at low speed for at least 2 minutes

irrespective of thermostat cycle during power on reset / change mode / unit recover from fault

22Apr 21, 2023

Internal use only

Errors Cool LED

7 Segment Indicator

Rooms sensor error (short/open) 1 blinks E1

Pipe water sensor error (short/open)

2 blinks E2

Water pump error 6 blinks E6

Pipe water temperature fault 5 blinks E5

Fault Diagnostics