Type
Code
Description
Solution
Unit working
statue
Blinking
times
Compressor speed
down or stop
S01
Protection
Indoor anti-freezing
protection in
cooling
Compressor speed down if coil temp. lower than 2
℃
; Compressor
stops if coil Temp. lower than -1
℃
; Compressor restarts if coil Temp.
higher than 6
℃
.
1.Check whether set temperature for cooling is too low; whether
system has too small water flow rate; check water system especially
the filter.
2.Check whether system has not enough refrigerant inside by
measuring the evaporating pressure.
3.Check whether ambient temperature is lower than 15
℃
.
Compressor stops
S02
Too small water
flow rate
System water flow rate is less than minimum allowable flow rate.
Check the water system, especially the filter; check the working
statue of water pump.
Warning but unit
keeps on working
S03
Water flow switch
failure
Water flow switch failed to work. Check whether flow switch is
broken or not well connected.
F30
Mixture valve 2
failure
Check MV2 cable connection; check whether PCB output voltage
signal; check whether MV2 is broken.
Unit keep on
working, mixture
valve 2 output
fixed to 0.
18
Failure
【
Indoor
】
Unit stops
F13
Room temp. sensor
failure
Check whether room temperature sensor is open, short-circuit or
value drifts too much. Replace it if necessary.
Unit stops
F14
Sanitary hot water
temp. sensor failure
Check whether sanitary hot water temperature sensor is open, short-
circuit or value drifts too much. Replace it if necessary.
Unit stops
F15
Cooling/heating
water temp. sensor
failure
Check whether cooling/heating water temperature sensor is open,
short-circuit or value drifts too much. Replace it if necessary.
Unit stops
F16
Unit water outlet
temp. sensor failure
Check whether unit water outlet temperature sensor is open, short-
circuit or value drifts too much. Replace it if necessary.
Unit stops
F17
Unit water inlet
temp. sensor failure
Check whether unit water inlet temperature sensor is open, short-
circuit or value drifts too much. Replace it if necessary.
Unit stops
F18
Indoor coil temp.
sensor failure
Check whether indoor temperature sensor is open, short-circuit or
value drifts too much. Replace it if necessary.
Unit keep on
working, mixture
valve 1 output
fixed to 0.
F21
Mixture valve 1
temperature sensor
failure
Check whether TV1 temperature sensor is open, short-circuit or
value drifts too much. Replace it if necessary.
Unit keep on
working, mixture
valve 2 output
fixed to 0.
F22
Mixture valve 2
temperature sensor
failure
Check whether TV2 temperature sensor is open, short-circuit or value
drifts too much. Replace it if necessary.
F25
Communication
between operation
panel and indoor
PCB or outdoor
PCB failure
Communication failure between operation panel and the indoor or
outdoor PCB. Check the cable connection in between. Check whether
the last three switches on outdoor power PCB are set to 001; Whether
four switches on indoor PCB are set to 1000. Unit recovers when
communication recovers.
Unit stops
F27
Indoor EEPROM
failure
Cut the unit power, connect CN213-5 and CN213-6 together,
repower the unit and then cut the power and cancel the connect. If
still not OK, replace the indoor PCB.
Unit keep on
working
F28
Water pump PWM
signal feedback
failure
Check water pump cable connection; check power supply to water
pump; check whether water pump is broken.
F29
Mixture valve 1
failure
Check MV1 cable connection; check whether PCB output voltage
signal; check whether MV1 is broken.
Unit keep on
working, mixture
valve 1 output
fixed to 0.
Unit keep on
working
7
3
6
4
5
8
11
12
1
13
14
17
97
9. Failure Code
Summary of Contents for Thermal Plus 12
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