Mitsubishi Electric PURY-P120Y(T)HMU-A, Service Handbook

Page: 305 / 387

[
IX
Troubleshooting ]
- 296 - HWE0803A GB
Items to be checked Phenomena Remedy
[3]
Check whether
the inverter is
damaged.
(No load) <P72 model> 1) Inverter-related problems are de-
tected. Connect the short-circuit con-
nector to CN6, and go to sec-
tion [1].
(1) Disconnect the inverter
output wire from the ter-
minals of the INV board
(SC-U, SC-V, SC-W). 2) Inverter voltage is not output. Replace the INV board.
(2) Disconnect the short-cir-
cuit connector from CN6
on the INV board. 3) There is an voltage imbalance be-
tween the wires.
Greater than 5% imbalance or 5V Replace the INV board.
(3) Put the outdoor unit into
operation.
Check the inverter output
voltage after the inverter
output frequency has sta-
bilized. 4) There is no voltage imbalance be-
tween the wires. Normal
*Reconnect the short-circuit
connector to CN6 after check-
ing the voltage.
<P96 and P120 models> 1) Inverter-related problems are de-
tected. Turn off SW1-1 and go to [1]
(1) Disconnect the inverter
output wire from the out-
put terminals (U, V, W) of
the IPM. 2) Inverter voltage is not output. Check the connection be-
tween the IPM and the
CNIPM on the INV board.
Replace the IPM.
If the problem persists, re-
place the INV board.
(2) Turn on SW1-1 on the
INV board. 3) There is an voltage imbalance be-
tween the wires.
Greater than 5% imbalance or 5V Replace the IPM.
If the problem persists, re-
place the INV board.
(3) Put the outdoor unit into
operation. 4) There is no voltage imbalance be-
tween the wires. Normal
*Turn off SW1-1
[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) There is an voltage imbalance be-
tween the wires.
Greater than 5% imbalance or 5V <P72 model>
Replace the INV board.
<P96 and P120 models>
Replace the IPM.
If the problem persists, re-
place the INV board.
If the problem persists after
replacing the above parts, go
to section [2].
[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
board failure. (1) Check the fan output wir-
ing. Connector contact failure
Œ
Board side (CNINV)
Œ
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 5 V.) Replace the FAN board.
2) The same error occurs even after
the operation is restarted.
[THMU-A]