MCAC-UTSM-2012--05 R407C MCCU Technical Manual
71
Part 3 Trouble shooting
1. Malfunctions
If any of the following malfunctions occur, stop operation of the air conditioner immediately. Turn off the power
switch, and contact the local after sales service center of manufacturer:
The fuse blows out frequently, or the circuit breaker protection occurs frequently.
Obstacles or water enter the air conditioner.
Condensing water leaks from indoor unit.
Other malfunctions occur.
If the air conditioner fails and does not meet the above phenomena, check the system as the following table:
Symptoms Causes Handling methods
The unit does not
work
Power supply fails. Operate after power resumes.
Power switch is not connected. Connect the power supply properly.
Fuse blows out or circuit breaker snaps off.
Replace the fuse or check whether
electric leakage occurs.
Air flowing
normally but
completely can’t
cooling
Temperature setting is improper.
Temperature setting is higher than the
room temperature in cooling mode. Or
temperature setting is lower than the
room temperature in heating mode.
3-minute protection of compressor. Waiting for 3 minutes.
The unit starts or
stops frequently
The system is lack of refrigerant. Or there is too
much refrigerant in the system.
Fix the leakage places, and charge the
proper quantity of refrigerant.
Air or non-condensable gas exists in the
refrigerant system.
Vacuum the system and charge
refrigerant again.
Compressor fails. Repair or replace the compressor.
The voltage is too high or too low. Install a voltage regulator.
The refrigerant pipe is obstructed. Locate and replace that part.
Poor cooling effect
The heat exchanger of outdoor unit or indoor unit
is too dirty.
Clean the heat exchanger.
The filter is too dirty. Clean the filter.
Air inlet or air outlet of the indoor/ outdoor unit is
blocked.
Remove obstacles to keep well
ventilating.
Doors or windows of the room are open. Close all the windows and doors.
Directly exposed to sunlight. Use curtain to obstruct sunlight.
Too many heat sources in the room. Reduce the heat sources.
The outdoor ambient temperature is too high. The cooling effect is poor but normal.
The system is lack of refrigerant.
Fix the leakage places, and charge the
proper quantity of refrigerant.
Poor heating
effect
The outdoor ambient temperature is lower than
-10℃.
Use an assistance heating device.
Doors or windows of the room are not closed
tightly.
Close the doors and windows properly.
The system is lack of refrigerant.
Fix the leakage places, and charge the
proper quantity of refrigerant.
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