Bypass Control; Bypass Solenoid Valve - Mitsubishi Electric PURY-(E)P200 Service Handbook

[ VII Control ]

-5- Bypass Control

Bypass solenoid valves (SV1a), which bypass the high- and low- pressure sides, perform the following functions.
(1) Bypass solenoid valve (SV1a) (ON = Open)
Operation
When each indoor unit 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
While the compressor is operating at the
minimum frequency and when the low pres-
sure (63LS) drops (3 or more minutes after
compressor startup)
When high pressure (63HS1) rises
(2) Bypass solenoid valve (SV9) (ON = Open)
Operation
When high pressure (63HS1) rises during
the heating operation
Others
(3) Bypass solenoid valve (SV2) (ON = Open)
Operation
When high pressure (63HS1) rises during
the heating operation
When startup or resuming operation after a
defrost cycle
During defrost cycle
Others
(4) Bypass solenoid valve (SV5b) (ON = Open)
Operation
When high pressure (63HS1) rises during
the heating operation
At startup
During defrost cycle
When returning to normal operation after
completion of the defrost cycle
Others
HWE07130
ON
Exception: OFF when 63HS1-63LS is 0.2MPa[29psi] or less
Exception: OFF when 63HS1-63LS is 0.2MPa[29psi] or less
When low pressure (63LS) drops
below 0.23MPa[33psi].
When 63HS1 exceeds
3.62MPa[525psi]
ON
When 63HS1 exceeds 3.50MPa
[507psi]
ON
When SV5b is OFF and the pres-
sure is 3.50MPa[507psi]or below
ON
When SV2 is OFF and the pressure
is 2.70MPa[391psi]or below
ON for 5 minutes and goes OFF
- 124 -
SV1a
OFF
ON for 4 minutes.
ON for 4 minutes.
Always ON.
ON for 3 minutes.
ON
When low pressure (63LS) ex-
ceeds 0.38MPa[55psi].
When 63HS1 is or below
3.43MPa[497psi] and 30 seconds
have passed
SV9
OFF
When SV5b is ON and the pressure
is 2.70MPa[391psi]or below
Always OFF
SV2
OFF
When 63HS1 exceeds 2.70MPa
[391psi]
OFF
ON
Always OFF
SV5b
OFF
When SV9 is ON and the pressure
is 3.50MPa[507psi]or below
ON
ON (open)
Always OFF
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