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12. SV2 valve control
The conditions for opening and closing the SV2 valve are shown in the table below.
13. Oil recovery control
1) This control enables periodic recovery of oil accumulating in the indoor unit or in the exchange pipe.
2) After continuous operation for 240 minutes, the lower limit for the compressor revolution number is
raised for 2 minutes and oil is recovered.
Non-operation
During Cooling
Operations
During Heating
Operations
During
Defrost
Operation
SV2 Valve “Open” Conditions
(1) When operation stopped after operating
(2) When power placed “ON”
(3)
When 30 second elapses after first startup
operation when power ON at TO ≤ 5° C
(4) When Ps ≤ 0.23 MPa
(5)
When 30 second elapses after first startup
operation when power ON at TC < 26°C
(6) When Ps ≤ 0.14 MPa
(7) When conditions for defrost satisfied.
(8) When conditions for defrost satisfied.
SV2 Valve “Close” Conditions
When operation started after operating or when 30 minutes
elapsed after opening SV2 under conditions (1) (2)
When 8 minutes elapsed after starting operation.
When Ps ≥ 0.27 MPa
When 8 minutes elapsed after starting operation or when
TC ≥ 26°C
When Ps ≥ 0.19 MPa
When 4-way valve is OFF during defrost startup.
When 2 minutes elapsed after four-way valve is ON after
defrost completion
3)
4) When the DOWN zone and the HOLD zone (UP prohibition) are superimposed for example during
current release control or discharge temperature release control, DOWN zone and the HOLD zone have
priority over oil recovery control.
During Cooling
During Heating
Control Conditions
Continuous cooling operation for 240 minutes
Continuous heating operation for 240 minutes
Control Details
Lower limit for compressor revolution number placed to 56 rps per
2 minutes
Lower limit for compressor revolution number placed to 70 rps per
2 minutes
During startup of oil recovery control, the compressor
revolution number during operation is lower than the
revolution number of the lower limit for control details.
When low
When high
The compressor rotation speed is raised to the lower limit
during control.
Operate according to indoor commands without lowering
the compressor rotation speed to the lower limit.
(In this case, the timer counts 2 minutes.)
ON
OFF
Open
Close
Compressor
revolution number
4-way valve
SV2
36rps
66rps
Defrost
start condition
Defrost
completion condition
Defrost operation
2 minutes