Low Pressure Protection Control - Daikin VRV II RXYQ8MY1K Service Manual

Protection Control
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]
Low pressure not limited
Pe<0.34MPa
Low pressure limited
All STD compressors
Pe<0.25MPa
Master unit:52 Hz + OFF + OFF
Slave unit:Stop
Pe<0.07MPa
Low pressure standby
[In heating operation]
Pe<0.17 MPa
INV upper limit frequency:
3-step down from current
compressor frequency
Pe<0.17 MPa
Pe<0.13 MPa
52 Hz + OFF + OFF
70
In the case of multi-outdoor-unit system, the entire system performs this control in the
following sequence.
Pe>0.39MPa
stop.
In the case of multi-outdoor-unit system, each outdoor unit performs this control
individually in the following sequence.
Low pressure not limited
&
Low pressure limited
Pe<0.07 MPa
Low pressure standby
Pe: LP pressure sensor detection
value for master unit
When occurring 4 times within 30 min.,
the malfunction code " E4 " is output.
Pe: LP pressure sensor detection
Pe >0.23 MPa
INV upper limit frequency = 210 Hz
Pe>0.20 MPa
INV upper limit frequency: 1-step /
20 sec up from current compressor
frequency
When occurring 4 times within 30 min.,
the malfunction code "E4" is output.
value for each outdoor unit
Si39-502A
Function