Mitsubishi Electric City Multi CMH-WM250V-A, Service Handbook

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[8-10 Troubleshooting Inverter Problems ]
BS_08_E chapter 8 -
45
8 Troub
le
sho
oting Bas
ed on Ob
ser
ved
Sy
mp
toms
<INV37YC> 3) An overcurrent error occurs during oper-
ation.
Error code : 4250
Detail code : 121,122 [8-10-6 Checking the Converter for
Damage during Compressor Oper-
ation]
4) An overcurrent error occurs immediately
after compressor startup.
Error code : 4250
Detail code :101,106,107,128 a. Check for refrigerant flooding.
→
When the problem persists after
compressor startup was repeated
several times, go to "d" after a cer-
tain time after energizing the com-
pressor or the heater.
If normal operation is restored,
check the belt heater for problems.
b. Check that there is a pressure dif-
ference between high and low
pressures after compressor start-
up.
→
Check the high pressure with
LED monitor for changes.
Replace the compressor if there is
no pressure difference. (the com-
pressor may be locked.)
c. Check for interphase voltage im-
balance.
d. Replace the INV board if no prob-
lems were found with the items a or
c.
e. If the problem persists after replac-
ing the inverter board, [8-10-3
Checking the Compressor for
Ground Fault and Coil Resistance
Problems]
5) An overvoltage error occurs during oper-
ation.
Error code : 4220
Detail code :109,110,112 [8-10-6 Checking the Converter for
Damage during Compressor Oper-
ation]
6) No problems were found with items 1)
through 5). Normal [8-10-6 Checking the Con-
verter for Damage during Com-
pressor Operation]
Items to be checked Phenomena Remedy
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