Checking The Converter For Damage During Compressor Operation; Checking The Fan Motor For Ground Fault And Coil Resistance Problems; Checking The Fan Board Error Detection Circuit At No Load - Mitsubishi Electric PUHY-P250YNW-A Service Handbook

[8-9 Troubleshooting Inverter Problems ]
8-9-6

Checking the Converter for Damage during Compressor Operation

Items to be checked
(1) Operate the outdoor unit.
(2) Check the BUS voltage after the
converter circuit went into oper-
ation and the BUS voltage has
boost.
*The voltage generally boost at
or above 80 rps, depending on
the power source voltage.
8-9-7

Checking the Fan Motor for Ground Fault and Coil Resistance Problems

Items to be checked
Remove fan motor winding. Check
insulation resistance and coil resis-
tance.
8-9-8

Checking the Fan Board Error Detection Circuit at No Load

Items to be checked
(1) Stop the unit.
Turn off the breaker.
*Be sure to turn off the power.
(2) Disconnect the output wiring
to the fan motor.
Disconnect connector
RYFAN1.
(3) Turn on the breaker.
(4) Operate the unit.
BS_08_C
Phenomena
1) BUS voltage does not boost (does
not change) BUS voltage does not
boost to approximately between
650 and 750 VDC, or the following
errors are detected.
Error code : 4220
Detail code : 123
2) An overcurrent error occurs after
converter circuit goes into opera-
tion.
Error code : 4250
Detail code : 121,122
3) An overvoltage error occurs after
converter circuit goes into opera-
tion.
Error code : 4220
Detail code : 109,110,112
4) No problems were found with items
1) through 3).
Phenomena
1) Fan motor insulation failure.
If < 1 MΩ, Defect.
2) Fan motor wire failure.
Target coil resistance: Approx. 10 Ω.
(Changes with temperature)
Phenomena
1) An error other than current sensor er-
ror (5305, 5306: Detail code 135) is
detected during operation.
2) Current sensor fault
Error code: 5305, 5306
Detail code: 135
Remedy
Replace the inverter board.
a.If the problem persists after startup, re-
place the inverter board.
b.If the problem persists after replacing
the inverter board, replace the DCL.
a.If the problem persists after startup, re-
place the inverter board.
b.If the problem persists after replacing
the inverter board, replace the DCL.
Normal
Remedy
Change fan motor.
Change fan motor.
Remedy
Replace the fan board.
Normal
*When done checking, reconnect all
connectors as they were. Unless
they are properly reconnected, cur-
rent sensor fault will not be resolved.
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