Panasonic U-10MF1E8 Service Manual page 24

6. Operation of Solenoid Valves
6-3. Balance Valve (BALV)
This valve moves some of the oil from the oil separator to the balance tube.
(1) When unit is stopped
This valve is always OFF.
(2) When unit is operating
(A) This valve is ON when separator oil self-recovery control is in progress.
1
(B) This valve is ON when unit refrigerant oil recovery control is in progress (oil-supply unit).
(C) This valve turns ON for 30 seconds each time a constant-speed compressor starts.
(D) This valve turns ON for 60 seconds after defrost control ends.
6-4. Recovery Valve (ORVR)
This valve recovers refrigerant oil from the balance tube to the compressor.
(1) When unit is stopped
This valve is always OFF.
(2) When unit is operating
(A) This valve is ON when separator oil self-recovery control is in progress.
(B) This valve is ON when unit refrigerant oil recovery control is in progress (oil-receiving unit).
(C) This valve is ON when control for insufficient gas is in progress.
(D) This valve turns ON for 60 seconds after a constant-speed compressor starts.
(E) This valve turns ON for 120 seconds after defrost control ends.
(F) This valve turns ON for 10 seconds after the outdoor unit stops.
(G) This valve remains OFF at all times other than (A) – (F) above.
6-5. Bypass Valve (BPV)
This valve flushes the oil from the balance tubes. In addition, it is used for recovering refrigerant from stopped
outdoor units during cooling operation.
(1) When unit is stopped
This valve is always OFF.
(2) When unit is operating
This valve is ON at the oil-supply outdoor unit when unit refrigerant oil recovery control is in progress.
* This valve repeatedly turns ON/OFF at regular intervals during unit refrigerant oil recovery control. (It is not
constantly ON.)
1 - 18
3-WAY SYSTEM
Control Functions