GMV5 DC INVERTER VRF UNITS SERVICE MANUAL 
184 
7. As shown in the figure below, put the black test probe to pad W (RD) and the red test probe to pad NW 
(make sure the moisture proof tape is removed). In normal cases, the multimeter should read 0.39±0.3 V. 
If it is ―0‖ or infinitely great, the IPM module is faulty. 
 
1.2 Precondition: Units cannot be normally started.   
Step 1: 
Disconnect the power supply of the units and open the electric junction box of the compressor to see 
whether wiring of the compressor is intact.   
Step 2: 
Measure resistance  between  two  wiring  terminals (U, V, W).  The  resistance value range should be 
0.5~2.0 Ω.   
 
Measure  the  resistance  to  earth  of  each  wiring  terminal.  The  value  should  be  10  MΩ.  If  not,  the 
compressor has an internal fault.   
Step 3: 
Check the solenoid valves of the system, include electric expansion valves, oil return valves, and oil 
balance valves. Refer to the preceding section for the test method.   
Step 4: 
Check the IPM module. Refer to the preceding section for the test method. 
Measure 
resistance 
between two 
wiring terminals 
using a multimeter 
Measure the 
resistance to earth of 
each wiring terminal 
one after another