Low Pressure Protection Control - Daikin VRV III-S RXYMQ36 48PVJU Service Manual

SiUS34-907
4.2

Low Pressure Protection Control

This low pressure protection control is used to protect compressors against the transient decrease of low
pressure.
[In cooling operation]
Low pressure
limited
[In heating operation]
Pe<24.7 psi
Low pressure limited
Function
Low pressure not limited
Pe<36.3 psi Pe>56.6 psi
36Hz Unload
Pe<10.2 psi
Low-pressure
standby
Low pressure not limited
INV. upper limit frequency :
3-step down from current
Pe<24.7 psi After 10 sec.
Current step limited
Pe>29 psi After 15 sec.
INV. upper limit frequency :
1-step up from current
compressor frequency
Pe< 10.2 psi
Low-pressure
standby
Pe: Low-pressure sensor detection value
Hot gas SVP = OFF
Pe<21.8 psi
Hot gas SVP = ON
When occurring 3 times within 30 min.,
the malfunction code "E4" is output.
Pe: Low-pressure sensor detection value
• Pe>13.1 psi
• Ts-Teg<14.4 degree
or
&
• Pe>8.7 psi
When occurring 3 times within 30 min.,
the malfunction code "E4" is output.
Protection Control
Pe>43.5 psi
Hot gas SVP = OFF
Pe<17.4 psi Pe>24.7 psi
Hot gas SVP = ON
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