Low Pressure Protection Control - Daikin RXYQ96PYDN Service Manual

SiUS34-801A_b
8.2

Low Pressure Protection Control

This low pressure protection control is used to protect compressors against the transient decrease
of low pressure.
[In cooling operation]
Pe_min<49.3psi
Pe_min<21.75psi
VRVIII R-410A Heat Pump 60Hz
Because of common low pressure, the following control is performed in the system.
Pe_min indicates the minimum value within the system.
Normal Operation
During the control
of low pressure
protection
For any model other than 144PTJU:
210Hz+OFF (upper)
For Model 144PTJU:
1/2 of compressor STEP
Pe_min<36.25psi
For any model other than 144PTJU:
52Hz+OFF (upper limit)
For Model 144PTJU:
52Hz+52Hz
Hot gas solenoid valve (Y5S, 144PTJU: Y4S)
ON
Pe_min<10.15psi
Restart standby (up to 3 times
within a period of 30 min.)
Pe_min>56.55psi
Pe_min>42.05psi
When occurring 4 times within 30 min.,
the malfunction code [E4] is displayed.
Protection Control
65