Daikin VRV II REYQ10MY1B, Service Manual

Page: 91 / 309

Protection Control Si39-306
80 Function
4. Protection Control
4.1 High Pressure Protection Control
This high pressure protection control is used to prevent the activation of protection devices due
to abnormal increase of high pressure and to protect compressors against the transient
increase of high pressure.
[In cooling operation]
In the case of multi-outdoor-unit system, each outdoor unit performs this control
individually in the following sequence.
[In heating operation or simultaneous cooling/heating operation]
In the case of multi-outdoor-unit system, the entire system performs this control in the
following sequence.
High pressure not limited
Pc>3.48MPa
High pressure standby
INV upper limit frequency = 210 Hz
High pressure limited
Pc>3.48MPa
Pc>3.58MPa
Pc<3.2MPa
Pc>3.53MPa
STD compressor
standby for 5 mins
Pc: HP pressure sensor detection
value for each outdoor unit
When occurring 3 times within
30 min., HPS is activated without high
pressure standby, thus outputting the
malfunction code “E3”.
INV upper limit frequency :
3-step / 10 sec down from
current compressor frequency
INV upper limit frequency:
1-step / 20 sec up from
current compressor frequency
High pressure not limited
Pc>3.38MPa
Lower-priority compressor stops.
High pressure limited
Pc>3.38MPa
Master unit: 52 Hz + OFF + OFF
Slave unit: All units stop.
Pc>3.49MPa
High pressure standby
Pc>3.58MPa
Pc<3.0MPa
Pc: HP pressure sensor detection
value for master unit
When occurring 3 times within
30 min., HPS is activated without high
pressure standby, thus outputting the
malfunction code “E3” .