Mitsubishi PWFY-P36NMU-E-BU Service Handbook page 65

-3- Solenoid Valve
Check whether the output signal from the control board and the operation of the solenoid valve match.
Setting the self-diagnosis switch (SW1) as shown in the figure below causes the ON signal of each relay to be
output to the LED's.
Each LED shows whether the relays for the following parts are ON or OFF. LEDs light up when relays are ON.
The circuits on some parts are closed when the relays are ON. Refer to the following instructions.
SW1
SW1
1 2 3 4 5 6 7 8 9 10
ON
When there is a problem with a solenoid valve, first check for loose solenoid valve coil, broken lead wire,
incorrect connecter connections on the circuit board, and broken wire at the connectors.
(1) In case of SV1 (Bypass valve)
This solenoid valve opens when powered (Relay ON).
1) This valve turns on during defrost, and its operation can be verified on the LED or by the operation sound it makes
when it closes.
2) The open or closed status of the valve can be verified by measuring the temperature of the pipe at the downstream
of SV1. When the valve is closed, pipes will be hot. Do not touch the pipe to check its temperature.
LD1 LD2
Upper
L o w r e
Display
LD3 LD4 LD5
SV1
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LD6 LD7 LD8