Low Pressure Protection Control - Daikin VRV II-Q RQYQ8-48PY1B Service Manual

Detailed Control Functions

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.
(3 times per 60 minutes at max.)
52
Normal operation
Pe < 0.34 MPa
*1
( 0.20 MPa)
All STD compressors stop
Pe < 0.25 MPa
*1
( 0.15 MPa)
Master unit: 52 Hz + OFF + OFF
Slave unit: ALL unit stop
Pe < 0.15 MPa
*1
( 0.10 MPa)
Solenoid valve (hot gas) (Y1S): ON
Pe < 0.07 MPa
Restart standby
Pe > 0.39 MPa
Pe: Low pressure sensor detection value
for master unit
*1
Value in the thermal storage operation
Pe > 0.29 MPa
Low pressure standby
4 times within 60 minutes
Stop due to error
E4
(" " displayed)
SiBE341027
Function