GMV5 DC INVERTER VRF UNITS SERVICE MANUAL 
165 
Attachment: How to check whether the IPM module is damaged 
1. Preparation: Find a digital multi-meter and switch it to the diode. Remove U, V and W cables of the 
compressor from the drive board two minutes after the system is powered off. Make sure that it is tested 
at least two minutes after the system is powered off.   
2. Method: Use the black probe of the multi-meter to touch the place marked by P in the follow picture 
and the red probe to touch places marked by U, V and W  respectively  and  record  readings of the 
multi-meter. Use the red probe to touch the place marked by N and black probe to touch places marked 
by U, V and W respectively and record readings of the multi-meter.   
3. Analyzing: If the reading ranges between 0.3 V and 0.7 V in the above-mentioned six scenarios, the 
IPM module is normal. If the reading is 0 in one or multiple scenarios, the IPM module is damaged.   
 
(4) Variable-frequency compressor drive board IPM over-temperature fault (ODU fault P8) 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Check if the fault 
occurs when the 
system is powered on. 
Check if the IPM module is 
screwed well and thermal gel 
is applied on the surface. 
 
Replace the 
compressor's drive 
board. 
Screw the IPM module 
properly and apply 
thermal gel on the 
surface.