Bypass Control - Mitsubishi Electric PUHY-RP200 Service Handbook

[ VII Control ]

-5- Bypass Control

Bypass solenoid valves (SV1(a,b)), which bypass the high- and low- pressure sides, perform the following functions.
(1) Bypass solenoid valve (SV1a) (ON = Open)
Operation
At compressor startup
After the restoration of thermo or 3 minutes
after restart
During cooling or heating operation with the
compressor stopped
After the operation has stopped
During defrost operation
During refrigerant oil recovery
When the low pressure (63LS) drops
(2) Bypass solenoid valve (SV1b) (ON = Open)
Operation
At compressor startup
After the restoration of thermo or 3 minutes
after restart
During cooling mode and when the com-
pressor is not in operation
During heating mode and when the com-
pressor is not in operation
After the operation has stopped
During defrost operation
During refrigerant oil recovery
When the low pressure (63LS) drops
HWE10010
ON
ON for 4 minutes.
SV1a turns off during refrigerant oil recovery that takes place after a low-
frequency operation (both in the cooling and heating modes).
SV1a turns on if the low pressure
(63LS) drops below 0.23 MPa while
the compressor is operating at the
minimum frequency.
ON
ON for 4 minutes.
SV1b turns on for three minutes, and turns on when the formula LPS -
LPS ” 0.2 MPa is satisfied.
SV1b turns on for three minutes, and turns on when the formula LPS -
LPS ” 0.2 MPa is satisfied.
SV1a turns off during refrigerant oil recovery that takes place after a low-
frequency operation (both in the cooling and heating modes).
SV1a turns on if the low pressure
(63LS) drops below 0.23 MPa while
the compressor is operating at the
minimum frequency.
- 96 -
SV1a
OFF
ON for 4 minutes.
Always OFF
Always OFF
Always ON
SV1a turns off if the low pressure
(63LS) reaches 0.38 MPa or above.
SV1b
OFF
ON for 4 minutes.
Always OFF
Always ON
SV1a turns off if the low pressure
(63LS) reaches 0.38 MPa or above.
GB