Panasonic Shows U-26PE1U6 Technical Data & Service Manual page 173

(2) [Alarm "P26"]
HIC PCB trouble)
Is power OK?
circuit wiring,
connector
connections, and
reactor
connections
Has filter PCB
RY001 or RY002
relay activated?
Disconnect
U.V.W. output
terminal on HIC PCB and
start operation.
Does alarm
compressor OK?
(Check for layer
short circuit.)
resistance
between
each terminal on
HIC PCB OK?
(See following
Replace outdoor unit
control PCB.
IGBT short-circuit protection on inverter control (IPDU) PCB
No
Yes
Are
No
OK?
Yes
No
Yes
Has filter PCB
AC fuse blown?
No
"P26"
occur?
Yes
Is
No
Yes
Is
Check HIC PCB.
No
Replace if PCB
has failed.
page.)
Yes
Correct power line.
Correct.
Yes
Replace filter PCB.
No
Replace HIC PCB.
Replace compressor.
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4. Service procedures
4