UNICA
Sanitary water heat pump
28
11.6
MALFUNCTIONING OF THE UNIT AND ERROR CODES
When an error occurs or the protection mode is set automatically, the circuit board and the wired controller will both display the
error message.
Protection/
Malfunction
Error code
LED indicator
Possible reasons
Corrective actions
Standby Dark
Normal running
Bright
Lower tank water
temp. sensor failure
P1
☆
●
(1flash 1 dark)
1) The sensor open circuit
2) The sensor short circuit
1) Check the sensor connection
2) Replace the sensor
Upper tank water
temp. sensor failure
P2
☆☆
●
(2 flashes 1 dark)
1) The sensor open circuit
2) The sensor short circuit
1) Check the sensor connection
2) Replace the sensor
Evaporator coil
temp. sensor failure
P3
☆☆☆
●
(3 flashes 1 dark)
1) The sensor open circuit
2) The sensor short circuit
1) Check the sensor connection
2) Replace the sensor
Return gas temp
sensor failure
P4
☆☆☆☆
●
(4 flashes 1 dark)
1) The sensor open circuit
2) The sensor short circuit
1) Check the sensor connection
2) Replace the sensor
Ambient temp.
sensor failure
P5
☆☆☆☆☆
●
(5 flashes 1 dark)
1) The sensor open circuit
2) The sensor short circuit
1) Check the sensor connection
2) Replace the sensor
Hot Sanitary / Solar
temp. sensor failure
P6 Dark
1) The sensor open circuit
2) The sensor short circuit
1) Check the sensor connection
2) Replace the sensor
Situation of remote
on/off signal
P7 Dark
When remote signal is on, no P7
will be showed on the controller,
when remote signal is off, P7 will
be displayed. It is not an error
code, but a situation for remote
on/off signal.
T6 too high
temp.protection
P8 Dark
1) T6 too high temp.
2) T6 sensor has problem
1) P8 appears at 125°C and disappears at
120°C
2) Check and if it’s necessary replace the
sensor
High pressure
protection (HP
Switch)
E1
☆☆☆☆☆☆
●
(6 flashes 1 dark)
1) Too high air inlet temp
2) Less water in the tank
3) The electronic expansion valve
assembly blocked
4) Too much refrigerant
5) The HP switch damaged
6) The uncompressed gas is in
refrigerant system
1) Check if the air inlet temp is over the
working limit
2) Check if the tank is full of water. If not,
charge water
3) Replace the electronic expansion valve
assembly
4) Discharge some refrigerant
5) Replace a new switch
6) Discharge and then recharge the refrigerant
Low pressure
protection (LP
Switch)
E2
☆☆☆☆☆☆☆
●
(7 flashes 1 dark)
1) Too low air inlet temp
2) The electronic expansion valve
assembly blocked
3) Too less refrigerant
4) The LP switch damaged
5) The fan assembly can not work
1) Check if the air inlet temp is over the
working limit
2) Replace the electronic expansion valve
assembly
3) Charge some refrigerant
4) Replace a new switch
5) Check if the fan working when the
compressor working. If not, some problems
with the fan assembly
Over heat protection
(T85°C Switch)
E3
☆☆☆☆☆☆☆☆
●
(8 flashes 1 dark)
1) Too high tank water temp
2) The T85°C switch damaged
1) If the tank water temp is over 85°C, the
switch will open and the e-heater will stop for
protection. After the water comes to normal
temp, the protection is auto-reset
2) Replace a new switch
Flow switch
E5
☆☆☆☆☆☆☆☆☆
●
(9 flashes 1 dark)
No water flow detected:
1) Pump not powered
2) Pump malfunction
3) Dirty water filter
4) Flow switch malfunction
1) Check pump power supply
2) Verify pump electrical connections and
pump rotation. If necessary replace the
pump
3) Clean the filter
4) Check the flow switch contacts and
functioning
Defrost
Defrosting
indicate
☆☆☆☆☆☆☆☆
(all long flashes)
Communication
failure
E8 Bright
