Mitsubishi Electric PFAV-P250VM-E Service Manual page 214

[ X Troubleshooting ]
[3] (1)
Check whether
the inverter is
damaged.
(No load)
(2)
(3)
[4] Put the outdoor unit into oper-
Check whether ation.
the inverter is Check the inverter output volt-
damaged. age after the inverter output
(During com- frequency has stabilized.
pressor opera-
tion)
[5] Remove the wire for the out-
Check the fan door fan motor, and check the
motor ground fan motor megger and the
fault or the winding resistance.
winding.
[6] (1)
Check the FAN
board failure.
(2)
(3)
HWE10190
Items to be checked
Disconnect the inverter
output wire from the ter-
minals of the INV board
(SC-U, SC-V, SC-W).
Disconnect the short-cir-
cuit connector from CN6
on the INV board.
Put the outdoor unit into
operation.
Check the inverter output
voltage after the inverter
output frequency has sta-
bilized.
Check the fan output wir-
ing.
Check the connector CN-
VDC connection.
Check the FAN board
failure.
Phenomena
1) Inverter-related problems are de-
tected.
2) Inverter voltage is not output at the
terminals (SC-U, SC-V, and SC-W)
3) There is an voltage imbalance be-
tween the wires.
Greater than 5% imbalance or 5V
4) There is no voltage imbalance be-
tween the wires.
1) Overcurrent error occurs immediate-
ly after the compressor startup.
(4250 Detail code No.101,106,107)
2) After the inverter output voltage be-
came stable, an imbalance (stated
below) is seen between each wires.
Greater than the larger of the follow-
ing values: imbalance of 5% or 5V
1) Fan motor megger failure
Failure when the megger is 1Mohm
or less.
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
Connector contact failure
Board side (CNINV)
Fan motor side
Cnnector contact 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 5 V.)
2) The same error occurs even after
the operation is restarted.
- 205 -
Remedy
Connect the short-circuit con-
nector to CN6, and go to sec-
tion [1].
Replace the INV board.
Replace the INV board.
Normal
*Reconnect the short-circuit
connector to CN6 after check-
ing the voltage.
a) Go over the check items [1]
through [3] to find the problem.
b) Check if the high/low pressure
are in proper balance.
c) Check that no liquid refrigerant is
present in the compressor.
→Proceed to d) if no improve-
ment is seen after several times
of reboot.
Even if it was recovered after the
reboot, check the crankcase
heater just to make sure there is
no problem with it.
d) After the reboot, check if there is
sufficient pressure difference
between high and low pressure.
→Check on LED monitor if the
high pressure changes.
If it does not, replace the com-
pressor.
(The compressor may be
locked.)
In the case of imbalance, re-
place the INV board.
Even if there is no imbalance
seen, check the crankcase
heater just to make sure there
is no problem with it.
→Some liquid refrigerant
might have been present in the
compressor when the problem
occurred.
Replace the fan motor.
ohm)
Connect the connector.
Connect the connector.
Replace the FAN board.
GB