Midea Precision AC Technical Manual MCAC-PDSM-2013-01
88
8. Trouble shooting
When the system is suddenly having a demand, but there is a failure or invalidation which led to
non-workable, and then it cannot meet environmental needs. So it is necessary to periodically do the
functional test for the system components. Controller provides field manual opening and closing
function for all parts, and use for self-detecting the functional components’ states of the system.
Detailed operations can be checked by system self-diagnostic function.
During the device operation, the internal unit may have a deadly high voltage. It only allow
specialized technical person to do the unit maintenance operation, and must be especially careful
during the troubleshooting with electricity.
Common faults and handling methods of indoor fan
Symptom
Probable reason
Check items or handling methods
Fan no
working
No main power supply
Check the voltage between A, B, C.
Overload, air switch is broken off
Manual reset, check the average current value.
Contactor cannot contact together
Check whether has 24V AC voltage between 28
and 03. (Wire numbers) If it has, then the
contactor has error, change it.
Control panel error
Check whether has 24V AC voltage between 28
and 03. If not, the control panel has error.
Air flow lost switch alarm (activate)
Check whether the belt has loosened or fan motor
has error, if not, then check whether the air flow
collecting plastic pip has abnormal position.
Fan error.
Replace it.
Common faults and handling methods of dehumidification system
Symptom
Probable reason
Check items or handling methods
No
dehumidification
effect
System does not require carrying out dehumidification.
Check the control system status.
Contactor of compressor cannot contact together.
Refers to refrigerant system
handling methods.
Compressor does not operate, the air switch broke off.
Check the air switch, contacting
points, check the air switch
voltage.
Dehumidification solenoid valve error
1, Check whether has 24V
voltage between wire 33 and wire
03.
2, Check whether reliable installs
the wires and valves.
