Protection Control - Daikin VRV II-Q RQYQ8-48PY1B Service Manual

SiBE341027
2.5

Protection Control

2.5.1 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]
In case of multi-outdoor-unit system, each outdoor unit performs this control individually in the following sequence.
Pc > 3.47 MPa
•Pc > 3.55 MPa
&
•After 10 seconds
STD compressor 2: OFF
•Pc > 3.55 MPa
& &
•After 10 seconds
STD compressor 1: OFF
•Pc > 3.55 MPa
&
•After 10 seconds
INV. compressor: 52 Hz
(2 times per 30 minutes at max.)
[In heating]
In case of multi-outdoor-unit system, the following control is performed in the entire system.
Pc > 2.94 MPa
Compressor system 7
step down / 10 seconds
Pc > 3.04 MPa
Compressor system
Master unit: 52 Hz + OFF + OFF
Slave unit: ALL unit stop
(2 times per 30 minutes at max.)
Function
Normal operation
(Without preconditions)
INV. compressor
3 step down
•Pc > 3.47 MPa
&
•After 10 seconds
Pc > 3.64 MPa
Restart standby
Normal operation
Pc < 2.75 MPa
Pc > 3.20 MPa
Restart standby
Pc: High pressure sensor detection
value for each outdoor unit
•Pc < 3.24 MPa
&
•After 15 seconds
Current step maintained
(Without preconditions)
Stop due to error
E3
(" " displayed)
Pc < 2.69
MPa
•Mater Tdi > 112˚C
OR
•Pc > 2.89 MPa
Stop due to error
E3
("
Pc: High pressure sensor detection value for master unit
Tdi: Value of INV. compressor discharge pipe temperature
Detailed Control Functions
Compressor step = Max. step
INV. compressor
1 step up
HPS (4.0 MPa) is activated
•Mater Tdi < 107˚C
•Pc < 2.69 MPa
Compressor system
Master: 52 Hz + OFF + OFF
Slave: ALL unit stop
HPS (4.0 MPa) is activated
" displayed)
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