Mitsubishi Electric PQHY-P72ZLMU-A Service Handbook page 333

[ IX Troubleshooting ]
(4) In the case of SV9 (Bypass valve) (PQRY only)
This solenoid valve opens when energized (when the relay is on)
This valve turns on when the value of 63HS1 is greater than 3.5 MPa [507psi] during Heating-only or Heating-main operation
at the minimum frequency. The valve position can be determined by measuring and monitoring the changes in the pipe tem-
perature on the downstream of SV9 while the unit is energized. When the valve is open, high-temperature gas refrigerant
passes through the pipe. Do not attempt to check the pipe temperature by touching the pipe.
HWE15150
Refrigerant Circuit diagram <PQRY>
1
Solenoid valve block
SV4a SV4b
SV4d
4
5 2
SV7a SV7b
THINV LEVINV
INV-HEX
ST13
LEV6
63LS
CJ2
SV9 ST18
Solenoid valve block(three compartments)
4
5
2
1
3
TH8
3
Water heat exchanger
(plate type)
TH7
LEV7
CV2a CV5a
SV6a
CV3a
5
2
3
1 is located behind 3
- 324 -
Water circuit
BV1
ST1
BV2
4
GB