Low Pressure Protection Control - Daikin RQYQ140-180PY1 Service Manual

SiBE341001

2.6.2 Low Pressure Protection Control

This low pressure protection control is used to protect compressors against the transient decrease of low pressure.
[In cooling operation]
★
Because of common low pressure, the following control is performed in the system.
Pe_min indicates the minimum value within the system.
Pe_min < 0.34 MPa
Single type:
Compressor step of the present
situation × 0.5
Multi type:
210 Hz + OFF + OFF (upper)
Pe_min < 0.25 MPa
Single type:
52 Hz + OFF
Multi type:
52Hz + OFF + OFF (upper limit)
Pe_min < 0.15 MPa
Function
Normal Operation
Pe_min > 0.39 MPa
Pe_min > 0.29 MPa
Hot gas solenoid valve ON
Pe_min < 0.07 MPa
Restart standby
(3 times per 60 min. at max.)
Detailed Control Functions
Restart standby
(4 times per 60 min. at max.)
Stop due to malfunction
(E4 displayed)
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