Low Pressure Protection Control - Daikin VRV II RXYQ5MY1B Service Manual

SiE39-404
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]
H
Low pressure not limited
Pe <0.35MPa
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]
H
Pe <0.16 MPa
124 Hz + OFF + OFF
Pe <0.16 MPa
Pe <0.13 MPa
52 Hz + OFF + OFF
Function
In the case of multi-outdoor-unit system, the entire system performs this control in the
following sequence.
Pe >0.40MPa
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
When occurring 3 times within 30 min.,
the malfunction code "E4" is output.
Pe: LP pressure sensor detection
value for each outdoor unit
Pe >0.25 MPa
INV upper limit frequency = 210 Hz
Pe >0.19 MPa
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.
Protection Control
value for master unit
95