Mitsubishi Electric CAHV-P500YB-HPB, Service Handbook

Page: 147 / 169

[
IX
Troubleshooting ]
- 140 -
HWE15070 GB
Items to be checked Phenomena Remedy
[4]
Check whether
the inverter is
damaged.
(During com-
pressor opera-
tion)
Put the outdoor unit into oper-
ation.
Check the inverter output volt-
age after the inverter output
frequency has stabilized.
1) Overcurrent-related problems oc-
cur immediately after compressor
startup.
Error code : 4250
Detail code : 101, 106, 107
a. Check items [1] through [3]
for problems.
b. Check that high and low
pressures are balanced.
c. Check that no liquid refrig-
erant is present in the
compressor.
→ Go to "d." when the
problem persists after
compressor startup was
repeated several times.
If normal operation is re-
stored, check the crank-
case heater for problems.
d. Check that there is a pres-
sure difference between
high and low pressures af-
ter compressor startup.
→ Check the high pressure
with LED monitor for
changes.
Replace the compressor if
there is no pressure differ-
ence. (the compressor
may be locked.)
2) There is a voltage imbalance be-
tween the wires after the inverter
output voltage is stabilized.
Greater than the larger of the fol-
lowing values: imbalance of 5% or
5V
Replace the INV board if there
is a voltage imbalance.
Check the crankcase heater
for problems if there is no volt-
age imbalance.
→ When the error occurred, liq-
uid refrigerant may have been
present in the compressor.
[5]
Check the fan
motor ground
fault or the
winding.
Remove the wire for the out-
door fan motor, and check the
fan motor megger and the
winding resistance.
1) Fan motor megger failure
Failure when the megger is 1Mohm
or less.
Replace the fan motor.
2) Fan motor disconnection
Standard: The winding resistance
is approximately several ohm.
(It varies depending on the temper-
ature, or while the inner thermo is
operating, it will be ohm)
[6]
Check the fan
inverter board
failure.
(1) Check the fan output wir-
ing.
Connector contact failure
 Board side (CNINV)
 Fan motor side
Connect the connector.
(2) Check the connector CN-
VDC connection.
Cnnector contact failure Connect the connector.
(3) Check the FAN board
failure.
1) The voltage imbalance among
each motor wiring during operation
(The voltage imbalance is greater
than the larger of the values repre-
sented by 5% or 5V.)
Replace the FAN board.
2) The same error occurs even after
the operation is restarted.
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