Daikin REYQ8-48PY1B, Service Manual

Page: 143 / 477

SiBE37-701_B Protection Control
Function 132
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]
★
The following control is performed in the entire system.
Pc_max indicates the maximum value within the system.
Normal Operation
Pc_max>3.47MPa Upper limit compressor step=max (Max. Step)
When high
pressure is limited
Upper limit
compressor step:
2-step down
Pc_max
>3.47MPa
After 10 sec.
Current step maintained
Pc_max
<3.24MPa
Pc_max
>3.55MPa
After 15 sec.
Upper limit
compressor step:
1-step up
After 10 sec.
For multi units:
When STD compressor is in operation
STD compressor standby
When STD compressor stays stopped
52Hz+OFF+OFF (upper limit)
For single unit:
8 to 12HP 52Hz+OFF
14, 16HP 52Hz+52Hz (upper limit)
Pc_max
>3.64MPa
High pressure
standby
When occurring 3 times within 30 min.,
high pressure switch is activated without
high pressure standby, thus outputting
the malfunction code “E3”.