Mitsubishi Electric PUHY-RP200 Service Handbook page 236

[ IX Troubleshooting ]
(3) SV1a and SV1b (bypass valve)
This solenoid valve turns on when energized (when the relay is on).
1) This valve turns on and stays on for four minutes at compressor startup. Proper operation can be verified with the LED or by
listening for the closing sound of the valve.
2) The valve position can be determined by measuring and monitoring the changes in the pipe temperature on the downstream
of SV1a and SV1b while the unit is energized. When the valve is open, high-temperature gas refrigerant passes through the
pipe. Do not touch the valve to check its temperature.
(Even while the valve is closed, a small amount of high-temperature gas still passes through the capillary tubes that are in-
stalled in parallel to the pipe, and the pipe temperature on the downstream of the valve may still be high.)
(4) SV3 (plate heat exchanger control valve)
This solenoid valve turns on when energized (when the relay is on).
This valve turns on during refrigerant oil recovery (heating mode only) or when the formula 63HS1 > 2.98 MPa is satisfied,
regardless of whether the compressor is operated at the minimum frequency during heating operation.
The valve position can be determined by measuring and monitoring the changes in the pipe temperature on the downstream
of SV3 while the unit is energized. When the valve is open, high-temperature gas refrigerant passes through the pipe. Do not
touch the valve to check its temperature.
(5) SV8 (automatic refrigerant charge control valve)
This solenoid valve turns on when energized (when the relay is on).
This valve turns ON or OFF as necessary during refrigerant oil recovery operation or refrigerant charge adjustment operation
(when SW4-3 is set to ON). The valve's status can be checked on the LED. The valve position can be determined by checking
to see if the refrigerant cylinder connected to the automatic refrigerant charging port becomes lighter during refrigerant oil re-
covery operation or refrigerant charge adjustment operation (while the unit is energized).
(6) SV5b (solenoid valve)
This valve is a shutoff valve that opens when energized. Proper operation can be verified on the LED and by listening for the
operation sound. During the cooling mode, SV5b is switched simultaneously with 21S4b, which may make it difficult to check
for proper operation of the SV5b by listening for the switching sound. If this is the case, pipe temperatures before and after
SV5b can be used to determine if the refrigerant is flowing in the pipe.
(7) LV9 (solenoid valve)
This valve is a shutoff valve that opens when energized. Proper operation can be verified on the LED and by listening for the
operation sound.
Do not give an impact from outside, as the outer hull will be deformed leading to the malfunction of the inner valve.
-4- Outdoor Unit Fan
To check the revolution of the fan, check the inverter output state on the self-diagnosis LED, as the inverter on the outdoor
fan controls the revolutions of the fan.
When starting the fan, the fan runs at full speed for 5 seconds.
When setting the DIP SW1 as shown in the figure below, the inverter output [%] will appear. 100% indicates the full speed
and 0% indicates the stopping.
As the revolution of the fan changes under control, at the interphase or when the indoor unit operation capacity is low, the
revolution of the fan may change.
If the fan does not move or it vibrates, Fan board problem or fan motor problem is suspected. Refer to IX [4] -6- (2) [5] "Check
the fan motor ground fault or the winding."(page 237) and IX [4] -6- (2) [6] "Check the Fan board failure."(page 238)
HWE10130
SW1
1 2 3 4 5 6 7 8 9 10
ON
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GB