Detailed Control Functions
SiBE341027
52
Function
2.5.2 Low Pressure Protection Control
This low pressure protection control is used to protect compressors against the transient decrease of low
pressure.
[In cooling]
In case of multi-outdoor-unit system, the following control is performed in the entire system.
Normal operation
All STD compressors stop
Solenoid valve (hot gas) (Y1S): ON
Restart standby
(3 times per 60 minutes at max.)
Stop due to error
(“
E4
” displayed)
Pe < 0.34 MPa
(
*1
0.20 MPa)
Pe < 0.15 MPa
(
*1
0.10 MPa)
Pe < 0.25 MPa
(
*1
0.15 MPa)
Pe > 0.39 MPa
Pe > 0.29 MPa
Pe < 0.07 MPa
Pe: Low pressure sensor detection value
for master unit
*1
Value in the thermal storage operation
Low pressure standby
4 times within 60 minutes
Master unit: 52 Hz + OFF + OFF
Slave unit: ALL unit stop
