37
Installation and Maintenance
Service Manual
Analysis or processing of some of the malfunction display:
1. Compressor discharge protection
Possible causes: shortage of refrigerant; blockage of air filter; poor ventilation or air flow short pass for condenser; the system
has noncondensing gas (such as air, water etc.); blockage of capillary assy (including filter); leakage inside four-way valve causes
incorrect operation; malfunction of compressor; malfunction of protection relay; malfunction of discharge sensor; outdoor temperature
too high.
Processing method: refer to the malfunction analysis in the above section.
2. Low voltage overcurrent protection
Possible cause: Sudden drop of supply voltage.
3. Communication malfunction
Processing method: Check if communication signal cable is connected reliably.
4. Sensor open or short circuit
Processing method: Check whether sensor is normal, connected with the corre sponding position on the controller and if damage of
lead wire is found.
5. Compressor over load protection
Possible causes: insufficient or too much refrigrant; blockage of capillary and increase of suction temp.; improper running of
compressor, burning in or stuck of bearing, damage of discharge valve; malfunction of protector.
Processing method: adjust refrigerant amount; replace the capillary; replace the compressor; use universal meter to check if the
contactor of compress or is fine when it is not overheated, if not replace the protector.
6. System malfunction
i.e.overload protection.When tube temperature(Check the temperature of outdoor heat exchanger when cooling and check the
temperatur e of indoor heat exchanger when heating) is too high, protection will be activated.
Possible causes: Outdoor temperature is too high when cooling; insufficient outdoor air circulation; refrigerant flow malfunction.
please refer to the malfunction analysis in the previous section for handling method .
7. IPM module protection
Processing method:Once the module malfunction happens,if it persists for a long time and can not be selfcanceled, cut off the power
and turn off the unit,and then re-energize the unit again after about 10 min.After repeating the procedure for sever times, if the
malfunction still exists,replace the module.
