Grundig GHP-MM08, Service Manual

Page: 46 / 83

46 / EN
Heat Pump Monobloc Inverter / User Manual
202202 Heat Pump Space Heater 44
4.4.4.3 Analysis and action
Notes:
1. Low pressure side blockages lead to higher discharge temperature, lower suction pressure,
lower compressor current, and a frosting occurs on the suction pipe.
2. Check the air side heat exchanger, the fan and air outlets for dirt and blockages.
3. Check water side heat exchanger, water piping, circulator pumps and water flow switch
for dirt and blockages.
4. The lack of refrigerant will lead to high discharge temperature, lower discharge and
suction pressures and compressor current, and may frost on the suction pipe. These issues will
disappear once sufficient refrigerant has been charged into the system.
5. Measure the resistance among the three terminals of the pressure sensor. If the
resistance is of the order of mega Ohms or infinite, the pressure sensor has failed.
Low pressure side is blocked? 1
P03
Yes
Ensure that there aren’t crushed
and bent copper pipes and the
filter on low pressure side
NO
Electronic expansion valve is locked dead?
Yes
When the power supply is on or
off, the electronic expansion valve
should have a reset sound. If no
any sound, replace EEV
NO
There is a poor heat transfer on air side or
water side heat exchanger? 2
Check heat exchangers carefully,
remove dirt and blockages
Yes
NO
Water flow rate is insufficient in
Cooling mode?
3
Check the water circuit, Make sure:
all the valves are open fully, the
water system is clean and has no
any clog, and remove air out of the
water system completely
Yes
NO
NO
The system is lack of refrigerant? 4
Add refrigerant enough or inspect
and fix the system leakage
Yes
Replace refrigerant system PCB
NO
Pressure sensor LPS is malfunction?
5
Replace the sensor LPS
Yes