71
Installation and Maintenance
Service Manual
38
Zero-crossing
malfunction of
outdoor unit
U9
During cooling and drying
operation, compressor and
outdoor fan stop while indoor
fan operates. During heating
operation, all loads stop.
Hardware malfunction
of outdoor units main
board;
1. Replace outdoor units
main board AP1;
39
Limit/decrease
frequency due to
freeze protection
FH
All loads operates normally,
while operation frequency of
compressor decreases.
Poor air return of
indoor unit or speed of
fan is too low
1. Check whether indoor
units horizontal louver
can close normally →
replace indoor units main
board → replace indoor
units motor;
9.2 Troubleshooting for Main Malfunction
Indoor unit:
1. Malfunction of Temperature Sensor F1, F2
Main detection points:
●
Is the wiring terminal between the temperature sensor and the controller loosened or poorly contacted?
●
Is there short circuit due to trip-over of the parts?
●
Is the temperature sensor broken?
●
Is mainboard broken?
Malfunction diagnosis process:
Is the wiring terminal between the
temperature sensor and the controller
loosened or poorly contacted?
Start
Insert the temperature
sensor tightly
Yes
Yes
Yes
Yes
Yes
Yes
No
No
No
No
No
No
Is malfunction
eliminated
Is malfunction
eliminated
Is malfunction
eliminated
Replace it with a
temperature sensor with
the same model
Make the parts upright
Is there short circuit due to trip-
over of the parts
Is the temperature sensor normal
according to the resistance table?
Replace the mainboard with
the same model.
End
