51
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 lter; poor ventilation or air ow short pass for condenser; the sys-
tem has noncondensing gas (such as air, water etc.); blockage of capillary assy (including lter); leakage inside four-way
valve causes incorrect operation; malfunction of compressor; malfunction of protection relay; malfunction of discharge sen-
sor; 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: insufcient 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 ne 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; insufcient outdoor air circulation; refrigerant ow malfunc-
tion.
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.
Error
code
Malfunction name AC status Possible causes
DC bus voltage drop
malfunction
Cool/Dry: compressor stops
operation, while indoor fan
operates; Heat: all loads stops
operation.
The power voltage is unstable.
Current detection
malfunction of unit
Cool: compressor and outdoor
fan stops operation, while indoor
fan operates; Heat: compressor,
outdoor fan and indoor fan
stops operation.
1. Is the complete unit lacking of refrigerant?
2. There’s malfunction for the circuit of control board of outdoor
unit. Replace the control board of outdoor unit.
4-way valve is abnormal This malfunction occurs when
the unit is heating. All loads
stops operation.
1. Power voltage is lower than AC175V;
2. Wiring terminal of 4-way valve is loose or broken;3. 4-way
valve is damaged. Replace the 4-way valve.
Malfunction of zero-
crossing signal of indoor
unit
Compressor, outdoor fan and
indoor fan stop operation.
1. The power is abnormal;
2. Main board of indoor unit is damaged.
Zero-crossing malfunction
of outdoor unit
Cool: compressor stops
operation, while indoor fan
operates; Heat: all loads stops
operation.
Replace the control board of outdoor unit.
Evaporator anti-freezing
protection
Not error code, it is the status code in cooling process
Anti cold air protection Not error code, it is the status code in cooling process
Defrosting Heat indicator Flash once/10s Not error code, it is the status code in cooling process
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