Low Pressure Protection Control - Daikin ALTHERMA HT ERSQ 011 AA 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 heating operation [R-410A]
Pe<0.17MPa
Low pressure limited
64
Low pressure not limited
INV upper limit frequency :
3-step down from current
compressor frequency
Pe<0.17MPa After 10 sec.
Current step limited
Pe>0.20MPa 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
• Pe>2.3MPa
or
Reach INV freq = MAX INV freq for each HP
When occurring 3 times within 30 min., the
malfunction code "E4" is output.
ESIE09-08A
Hot gas SVP = OFF
Pe<0.12MPa Pe>0.17MPa
Hot gas SVP = ON
Function