Low Pressure Protection Control - Daikin RXYQ96PYDN Service Manual

SiUS34-801A_b
[Heating Operation and Simultaneous Cooling / Heating Operation]
8.2

Low Pressure Protection Control

This low pressure protection control is used to protect compressors against the transient decrease
of low pressure.
[In cooling operation]
VRVIII R-410A Heat Recovery 60Hz
The following control is performed in the entire system.
Pc_max indicates the maximum value within the system.
Normal Operation
Pc_max>479.95psi
When high
pressure is limited
Compressor step:
7 STEP down
Pc_max
>495.9psi
Set the compressor
step to STEP 1
High pressure
standby
Because of common low pressure, the following control is performed in the system.
Pc_max<426.3psi
After 10 sec.
&
Pc_max>479.95psi
Pc_max>527.8psi
When occurring 3 times within
30 min., HPS is activated without high
pressure standby, thus outputting the
malfunction code [E3].
Protection Control
211