Specifications

Protection Control SiUS39-602
60 Function
4.2 Low Pressure Protection Control
This low pressure protection control is used to protect compressors against the transient
decrease of low pressure.
[In cooling operation]
[In heating operation]
Low pressure not limited
Pe<50 psi
Low pressure standby
Low pressure limited
All STD compressors
stop.
Master unit:52 Hz + OFF
Slave unit:Stop
Pe<36 psi
Pe>58 psi
Pe<10 psi
Pe: LP pressure sensor detection
value for master unit
When occurring 3 times within 30 min.,
the malfunction code “ E4 ” is output.
Pe<23 psi
Pe<19 psi
Pe >36 psi
INV upper limit frequency = 210 Hz
Pe<10 psi
&
Low pressure not limited
Low pressure standby
Low pressure limited
124 Hz + OFF
INV upper limit frequency: 1-step /
20 sec up from current compressor
frequency
52 Hz + OFF
Pe: LP pressure sensor detection
value for each outdoor unit
Pe>28 psi
Pe<23 psi
When occurring 3 times within 30 min.,
the malfunction code “E4” is output.