Low Pressure Protection Control - Daikin REYQ72 Serveice 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<50 psi
Low pressure limited
All STD compressors
Pe<36 psi
Master unit:52 Hz + OFF
Slave unit:Stop
Pe<10 psi
Low pressure standby
[In heating operation]
Pe<23 psi
124 Hz + OFF
Pe<23 psi
Pe<19 psi
52 Hz + OFF
60
Pe>58 psi
stop.
Low pressure not limited
&
Low pressure limited
Pe<10 psi
Low pressure standby
Pe: LP pressure sensor detection
value for master unit
When occurring 3 times within 30 min.,
the malfunction code " E4 " is output.
Pe: LP pressure sensor detection
value for each outdoor unit
Pe >36 psi
INV upper limit frequency = 210 Hz
Pe>28 psi
INV upper limit frequency: 1-step /
20 sec up from current compressor
frequency
When occurring 3 times within 30 min.,
the malfunction code "E4" is output.
SiUS39-602
Function