MCAC-VTSM-2016-04
R410A DC Inverter VRF V4 Plus W Series 50Hz
Troubleshooting 213
1) L0 troubleshooting
Step 1:
Compressor check
Measure the resistance between each two of U, V, W terminals of the compressor, all the resistance should be
the same and equal to 0.9~5 Ohms. (Fig. A and Fig. B)
Measure the resistance between each of U, V, W terminals of the compressor to ground (Fig. C), all the
resistance should trend to infinity (Fig. D), otherwise the compressor has been malfunction, needs to be
replaced.
Fig. A Fig.B Fig.C Fig.D
If the resistance value are normal, then go to step 2.
Step 2:
Module check
1) DC voltage between terminal P and terminal N should be 1.41 times of the local power supply voltage.
2) DC voltage between terminal 1 and 2 should be 510V
～
580V.
3) Discoonnect the terminal 3, 4, and 5 from inverter compressor. Measure the risistance between any two
terminals among terminal 1, 2, 3, 4, 5. All the values should be infinity. If any of the value approximates to 0,
the inverter module is damaged and should be replaced.
After replaced the inverter module, if the system is still abnormal, then go to step3.
Step 3:
DC generatrix check
Direction of the current in DC supply wire which is running through the inductor should be the same as the
direction of arrow marked on the inductor.
N
3
2
4
5
1
P
