This is the PDF excerpt of the Sanden Heat Pump G4 GAU-A45HPC error codes from the Sanden Heat Pump - Service Technical Manual Pages 19 to 21.
Sanden Heat Pump G4 GAU-A45HPC Error Code Example
"The HP will display an error code if it is unable to function normally.
Error codes are indicated by a red LED on the control panel. The control panel is visible via a small window at the right side of the heat pump and it can be accessed by removing the heat pump top cover (4 screws).
After a component is replaced or the inspection is completed, cycle power to the unit several times to confirm the error does not re-occur. Below is the list of the error codes. If the corrective action does not solve the error problem, a malfunction of the PCB valve is highly likely."
Error code
Reason for the error
Corrective action
H9
HP ambient (outdoor)
temperature thermistor error
Check the thermistor connectors on the main PCB or control PCB in the heat pump unit for any disconnection, fall-off, wire breakage or short circuit.
Measure resistance of the thermistor indicated by the error code.
HC
HP water outlet (outgoing)
temperature thermistor error
J3
HP discharge temperature
thermistor error
J5
HP suction temperature
thermistor error
J6
HP defrost temperature
thermistor error
J8
HP water inlet (return)
temperature thermistor error
H7
Tank temperature thermistor error
Check the thermistor cable on the terminal block in the heat pump unit for any disconnection, fall-off, wire breakage or short circuit.
Measure resistance of the thermistor indicated by the error code.
E6
Compressor booting error
Check the compressor connector.
Replace the main PCB or heat pump.
H6
Compressor revolution error
Check the supply voltage.
Measure resistance of each thermistor.
Measure resistance of coil of expansion valve to check open or short circuit.
Error code
Reason for the error
Corrective action
Replace the PCB or heat pump.
U0
Refrigerant leakage error
Measure resistance of each thermistor.
Measure resistance of coil of expansion valve to check open or short circuit.
Replace the main PCB or heat pump.
E1
Main PCB error
Replace the main PCB.
E2
L7
Control PCB error
Replace the control PCB.
F5
Communication error between main PCB to control PCB
Check the communication connector on the main PCB and control PCB.
Replace the main PCB or control PCB.
E8
High inlet current error
Check the installation location.
Check the supply voltage.
Replace the main PCB or heat pump.
H8
Current error
Replace the main PCB.
L4
High temperature of module error
Check the installation location.
Remove foreign objects from the evaporator coil (e.g. fallen leaves, grass, snow).
Check the fan motor is not flowing by dirt.
Replace the main PCB or fan motor.
L5
High outlet current error
Measure resistance of the discharged thermistor.
Measure resistance of coil of expansion valve to check open or short circuit.
Replace the main PCB or heat pump.
P4
Module temperature
thermistor error
Replace the main PCB.
U2
High voltage error
Check the supply voltage.
HJ
Water circuit error
Check the inlet water valve.
Check for any piping bend, blockage, kink or frozen.
Measure resistance of each thermistor.
Measure resistance of coil of expansion valve to check open or short circuit.
Replace the main PCB or heat pump.
EC
High water outlet error
Check the water circuit is not flowing by air, dirt or scaling.
If the water circulation pump is not working, replace the pump.
Measure resistance of water outlet (outgoing) thermistor.
Replace the main PCB.
E9
Water circulation pump error
Check the water is full in the tank.
If the water circulation pump is not working, replace the pump.
Check the revolution of pump by controller. If the revolution is low, replace the pump.
