Low Pressure Protection Control - Daikin REYQ-TA Series 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 Operation
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 < 0.17 MPa
(24.7 psi)
After 10 seconds
9-step down
Pe < 0.17 MPa
(24.7 psi)
Pe < 0.14 MPa
(20.3 psi)
21-step down
After 10 seconds
Pe < 0.13 MPa
(18.9 psi)
(3 times within 60 minutes)
75
Pe > 0.39 MPa
(56.6 psi)
Pe < 0.07 MPa (10.2 psi)
Upper limit compressor step: max (Max. Step)
Normal Operation
After 15 seconds
Current step
maintained
After 15 seconds
After 10 seconds
Compressor step: 1
Pe < 0.07 MPa
(10.2 psi)
Low pressure standby
Low pressure standby
(4 times within 60 minutes)
Abnormal stop
(E4 is displayed)
9-step up
Pe > 0.27 MPa
(39.2 psi)
Pe > 0.20 MPa
(29.0 psi)
3-step up
Low pressure standby
(4 times within 60 minutes)
Abnormal stop
(E4 is displayed)
SiUS371614E
Pe: Low pressure sensor
detection value for master
unit
Pe: Low pressure sensor
detection value for each
outdoor unit
Functions and Control