Low Pressure Protection Control - Daikin REYQ-XA Service Manual

Protection Control
6.2

Low Pressure Protection Control

This low pressure protection control is used to protect compressors against the transient decrease
of low pressure.
Cooling
Normal control
Pe < 0.25 MPa
(36.3 psi)
All compressors step: 1
Pe < 0.15 MPa
(21.8 psi)
Master unit: Compressor step: 1
Slave unit: All stop
Low pressure standby
(3 times within 60 minutes)
Heating
Pe < 0.10 MPa
(14.5 psi)
After 10 seconds
9-step down
Pe < 0.10 MPa
(14.5 psi)
Pe < 0.08 MPa
(11.6 psi)
21-step down
After 10 seconds
Pe < 0.07 MPa
(10.2 psi)
(3 times within 60 minutes)
119
Pe > 0.39 MPa
(56.6 psi)
Pe < 0.07 MPa (10.2 psi)
Upper limit compressor step: max (Max. Step)
Normal control
After 15 seconds
Current step
maintained
After 15 seconds
After 10 seconds
Compressor step: 1
Pe < 0.03 MPa
(4.35 psi)
Low pressure standby
Low pressure standby
(4 times within 60 minutes)
Abnormal stop
(E4 is displayed)
9-step up
Pe > 0.15 MPa
(21.8 psi)
Pe > 0.11 MPa
(16.0 psi)
3-step up
Low pressure standby
(4 times within 60 minutes)
Abnormal stop
(E4 is displayed)
SiUS371901E
Pe: Low pressure sensor
detection value for master
unit
Pe: Low pressure sensor
detection value for each
outdoor unit
Functions and Control