4220
(U9)
Voltage shortage /Overvoltage/PAM error/L1 open phase/
Primary current sensor error/Power synchronization signal error
●Diagnosis of defectives
Make sure to turn the power OFF before connecting/disconnecting
any connectors, or replacing boards.
Diagnosis Remedy
The black square (■) indicates a switch position.
Chart 2 of 2
Yes
Yes
No
Yes
No
No
Yes
7,8 6
The bus voltage can be displayed by an
operation of SW1 on the outdoor multi controller
circuit board.
Correct the CN5 wiring.
Continued from the previous page
Is the power supply normal?
Is the bus voltage normal?
The difference of the voltage between
the one read by the LED1 and 2, and the
one at the testpoints listed above is large.
Decrease of power supply voltage.
L1 open-phase.
Replace the outdoor power circuit board
(Defective outdoor power circuit board).
Replace the outdoor power circuit board
(Trouble of an input current detection
circuit is suspected.).
Check the power supply facility
(Check if a receiving electricity is lowered).
Check the bus voltage read by the microprocessor
with an operation of SW1 on the outdoor multi
controller circuit board.
Check the bus voltage at the test points
below on the outdoor power circuit board
using a tester.
Test points: CNDC 1–3pin
ON
OFF
1 2 3 4 5 6 7 8
SW1 Setting
Display on LED1,2
Unit
0–999.9 V
76
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