Specifications

SiUS39-602 Protection Control
Function 59
4. Protection Control
4.1 High Pressure Protection Control
This high pressure protection control is used to prevent the activation of protection devices due
to abnormal increase of high pressure and to protect compressors against the transient
increase of high pressure.
[In cooling operation]
[In heating operation]
High pressure not limited
Pc>505 psi
High pressure standby
INV upper limit frequency = 210 Hz
High pressure limited
Pc>505 psi
Pc>519 psi
Pc<464 psi
Pc>512 psi
STD compressor
standby for 5 mins
Pc: HP pressure sensor detection
value for each outdoor unit
When occurring 3 times within
30 min., HPS is activated without high
pressure standby, thus outputting the
malfunction code “E3”.
INV upper limit frequency :
3-step / 10 sec down from
current compressor frequency
INV upper limit frequency:
1-step / 20 sec up from
current compressor frequency
High pressure not limited
Pc>490 psi
Lower-priority compressor stops.
High pressure limited
Pc>490 psi
52 Hz + OFF
Pc>506 psi
High pressure standby
Pc>519 psi
Pc<435 psi
Pc: HP pressure sensor detection
value for master unit
When occurring 3 times within
30 min., HPS is activated without high
pressure standby, thus outputting the
malfunction code “E3” .