Low Pressure Protection Control - Daikin VRV IV-S RXTQ-TAVJU Series Service Manual

SiUS331604E
4.2

Low Pressure Protection Control

This low pressure protection control is used to protect compressors against transient decreases in low pressure.
Cooling operation
Low pressure not limited
Pe < 0.25 MPa
(36.3 psi)
Low pressure
limited
Pe < 0.07 MPa
(10.2 psi)
Heating operation
Pe < 0.17 MPa (24.7 psi)
Low pressure limited
Pe < 0.17 MPa (24.7 psi)
Pe > 0.20 MPa (29.0 psi)
Functions and Control
Pe > 0.39 MPa
(56.6 psi)
36 Hz Unload
Low pressure
standby
Low pressure not limited
Compressor upper limit
frequency: 3-step down from
current compressor frequency
After 10 seconds
Current step limited
After 15 seconds
Compressor upper limit
frequency: 1-step up from
current compressor frequency
Pe < 0.07 MPa (10.2 psi)
Low pressure
standby
Pe: Low pressure sensor detection value
Hot gas bypass valve: OFF
Pe < 0.15 MPa
(21.8 psi)
Hot gas bypass valve: ON
When occurring 3 times within 30 minutes,
E4
the error code is output.
Pe: Low pressure sensor detection value
• Pe > 0.09 MPa (13.1 psi)
OR
&
When occurring 3 times within 30 minutes,
E4
the error code is output.
Protection Control
Pe > 0.30 MPa
(43.5 psi)
• Ts – Teg < 8˚C (14.4˚F)
• Pe > 0.06 MPa (8.7 psi)
Hot gas bypass valve: OFF
Pe < 0.12 MPa
(17.4 psi)
Hot gas bypass valve: ON
Pe > 0.17 MPa
(24.7 psi)
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