Low Pressure Protection Control - Daikin VRV - WII Service Manual

SiUS30-604
6.2

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 < 49.3psi
Pe < 34.8psi
Less than 3 times
within 60 min.
[In heating or cooling/heating simultaneous operation] (When the outside unit heat exchanger
is used as evaporator.)
Pe < 91.3psi
Pe < 79.7psi
Less than 3 times
within 60 min.
Function
Normal operation
Compressor 52Hz
Hot gas solenoid valve (Y1S)
ON
Pe < 10.1psi
Low pressure standby
Normal control
Comp. upper limit down
1 step/10 sec.
Compressor 52Hz
Pe < 10.1psi
Low pressure standby
∗1 Pe: LP pressure sensor detection
∗2 This frequency control is carried
Pe > 56.5psi out in whole system.
Pe > 49.3psi
Pe < 34.8psi
When occurring 4 times within 60 min.,
the malfunction code "E4" is output.
Pe > 102.9psi
Pe > 98.6psi
Pe < 91.3psi
When occurring 4 times within 60 min.,
the malfunction code "E4" is output.
Protection Control
value for master unit
Hot gas solenoid valve (Y1S)
OFF
∗1 Pe: LP pressure sensor detection
value for each outside unit.
∗2 This frequency control is carried
out in each outside unit.
Comp. upper limit up
1 step/20 sec.
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