Service Manual

SiUS181631EA Protection Control
Functions and Control 61
4. Protection Control
4.1 High Pressure Protection Control
Outline High pressure protection control is used to prevent the activation of protection devices due to an
abnormal increase of high pressure and to protect compressors against the temporary increase of
high pressure.
Cooling Operation
Heating Operation
Pc > 3.47 MPa (1161 ftAq)After 10 sec.
Pc
> 3.47 MPa (1161 ftAq)
Pc
< 3.23 MPa (1081 ftAq)
Pc > 3.64 MPa (1218 ftAq)
Keeping the current step
After 15 sec.
High pressure not limited
High pressure limited
Pc: High pressure sensor detection value
When occurring 10 times within 60 minutes,
the high pressure switch is activated without
high pressure standby, and the error code
E3 is output.
Upper limit frequency = Max
(R19079)
High pressure
standby
Upper limit frequency: 1-step up
Upper limit frequency: 3-step down
High pressure drop
Pc > 3.04 MPa (1017 ftAq)After 10 sec.
Pc
> 3.04 MPa (1017 ftAq)
Pc
< 2.94 MPa (984 ftAq)
Pc > 3.64 MPa (1218 ftAq)
Keeping the current step
After 60 sec.
High pressure not limited
High pressure limited
Pc: High pressure sensor detection value
When occurring 10 times within 60 minutes,
the high pressure switch is activated without
high pressure standby, and the error code
E3 is output.
Pc < 2.89 MPa (967 ftAq)
(R19080)
High pressure
standby
Upper limit frequency: 1-step down
Upper limit frequency: 1-step up