Service manual

47
Be sure to use the analog voltmeter for measurement.
With the connector between compressor and IPM disconnected, activate the inverter and measure the balance of voltage between terminals.
<< Operation method>>
Start heating operation by pressing the EMERGENCY OPERATION switch
on the indoor unit. (test-run mode)
<<Measurement point>>
at 3 points
BLK-WHT
BLK-RED
WHT-RED
<<Judgment>>
Balanced································normal
Unbalanced···························abnomal (open phase)
Shutdown by overcurrent·······abnormal (short)
NOTE 1. Measure AC voltage, at 3 points more than one minute after the outdoor fan motor starts running.
2. The output voltage values in above table have tolerance withinJi20%.
w Measure AC voltage between
the lead wires at 3 points.
ACV
300
ACV
300
ACV
300
ACV
300
ACV
300
ACV
300
Normal
(Balanced)
Abnormal
(unbalanced)
BLK-WHT BLK-RED WHT-RED
BLK-WHT BLK-RED WHT-RED
Voltmeter indication
COOL
HEAT
120
130
110
Operational
frequency
[Hz]
Operation
mode
Model
MSZ09UN
MSZ12UN
MSZ09UN
MSZ12UN
Output
voltage
[V]
64
70
58
Disconnect the connector between compressor and IPM, and
measure resistance between terminals on the IPM.
<<Measurement point>>
at 6 points
BLK-WHT, WHT-BLK
BLK-RED, RED-BLK
WHT-RED, RED-WHT
<<Judgment>>
Infinite ["]···········normal
0~dozens of ······abnormal (short)
w Measure resistance between
the lead wires at 3 points
ohmmeter indication
normal
(infinite)
abnormal
(0~dozens of ")
X1
"
X1
"
Check of open phase
B
Check of open IPM
C
Check the voltage
between terminals.
Check the
compressor.
Disconnect the connector
between compressor and
IPM.
Refer to D “Check of compressor” on page 48.
No
Refer to B “Check of open phase” on page 47.
Replace the outdoor
electronic control P.C.
board.
Yes
Are voltages
balanced?
How to check inverter/ compressor
A
When OPERATION INDICATOR lamp flashes 5-time.
Outdoor unit does not operate.
OB297--2.qxp 04.2.4 4:21 PM Page 47