Low Pressure Protection Control - Daikin ERQ Service Manual

Protection Control
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]
Pe<0.25MPa
Low pressure
limited
Pe<0.07MPa
[In heating operation]
Pe<0.17MPa
Low pressure limited
Pe<0.17MPa
Pe>0.20MPa
34
Low pressure not limited
Pe>0.39MPa
36Hz Unload
Low pressure
standby
Low pressure not limited
INV upper limit frequency :
3-step down from current
compressor frequency
After 10 sec.
Current step limited
After 15 sec.
INV upper limit frequency :
1-step up from current
compressor frequency
Pe< 0.07MPa
Low pressure
standby
Pe: LP pressure sensor detection
value
Hot gas SVP = OFF
Pe<0.15MPa
Hot gas SVP = ON
When occurring 3 times within 30 min.,
the malfunction code "E4" is output.
Pe: LP pressure sensor detection
value
• Pe>0.09MPa
• Ts-Teg<8deg
or
&
• Pe>0.06MPa
When occurring 3 times within 30 min.,
the malfunction code "E4" is output.
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ESIE09-05
Pe>0.30MPa
Hot gas SVP = OFF
Pe<0.12MPa Pe>0.17MPa
Hot gas SVP = ON
Function