Daikin VRVIII-S, Service Manual

Page: 64 / 266

SiENBE34-703 Protection Control
Function 53
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]
[In heating operation]
Pe: LP pressure sensor detection
value
Low pressure not limited
Pe>0.39MPa
Pe<0.25MPa
Low pressure
limited
Hot gas SVP = OFF
Hot gas SVP = ON
Pe>0.30MPa Pe<0.15MPa
When occurring 3 times within 30 min.,
the malfunction code "E4" is output.
36Hz Unload
Pe<0.07MPa
Low pressure
standby
• Ts-Teg < 8deg
• Pe>0.06MPa
INV upper limit frequency :
3-step down from current
compressor frequency
INV upper limit frequency:
1-step up from current
compressor frequency
Hot gas SVP = OFF
Hot gas SVP = ON
Pe < 0.07MPa
Pe < 0.12MPa Pe > 0.17MPa
Pe > 0.09MPa
Current step limited
Low pressure not limited
Low pressure limited
Pe<0.17MPa After 10 sec.
After 15 sec. Pe>0.20MPa
Low pressure
standby
When occurring 3 times within 30 min.,
the malfunction code "E4" is output.
Pe: LP pressure sensor detection
value
&
or