MXZ-SM36NAMHZ Service Manual

78
OCH789
Check code
4220
(U9)
Chart 2 of 2
Voltage shortage/overvoltage/PAM error/L1 open phase/primary
current sensor error/power synchronization signal error
●Diagnosis of defects
Make sure to turn the power OFF before connecting/disconnecting
any connectors, or replacing boards.
Diagnosis Remedy
The black square (■) indicates a switch position.
No
7, 8
6
No
Yes
Yes
3-phase
Single-phase
No
Yes
No
Yes
The bus voltage can be displayed by an
operation of SW1 on the outdoor multi
controller circuit board.
Continued from the previous page.
Is the bus voltage normal?
Check the resistor connected to 52C relay
and reactor. Replace it if the resistor is
broken. Replace the outdoor power circuit
board if the resistor is not broken.
Operate the unit and check if the problem
occurs again.
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 multimeter.
Test points: CNDC 1-3 pin
Check the power supply voltage on the terminal block
of the outdoor unit.
Is the power supply normal?
Check the power supply facility.
Correct the CN5 wiring.
Is the outdoor unit
single-phase or 3-phase?
Replace the outdoor power circuit board
(Defective outdoor power circuit board).
Is CN5 connected properly
without any contact failure?
Is there any breakage of ACCT
on the noise lter circuit board?
Replace the noise lter circuit board.
Replace the outdoor power circuit board
(Defective outdoor power circuit board).
ON
OFF
1 2 3 4 5 6 7 8
SW1 Setting
Display on LED1,2 Unit
0–9999 V