Daikin R407C PLUS - Page 85

Outline of Control (Outdoor Unit) < Symbols using in this manual > Si33-105
74 Function R407C PLUS Series Heat Recovery System
3.5.2 Low Pressure Protection Control
The following control is provided to protect the compressors from abnormal decrease of low
pressure (LP).
"
1.Upper limit compressor operation : According to “Drooping step Table”. See next page.
Normal operation
Normal operation
H SVP : OFF
E4 malfunction
stop
Forced thermostat
OFF
LP<0.15MPa
LP<0.05MPa
LP>0.10MPa
LP<0.03MPa LP<0.0MPa
Compressor
operation
frequency
31Hz+OFF+OFF
LP<0.05MPa
SVP (for hot gas
bypass) : ON
LP<0.08MPa
SVP (for hot gas
bypass) : OFF
SVP (for hot gas
bypass) : ON
OR
• &
• Ta<Tes+5
• LP>0.20MPa
• 30 sec elapse
OR
• &
• &
• LP>0.13MPa
• Ta>5˚C
• LP<0.098MPa
• Ta≤5˚C
OR
• &
• &
• LP<0.08MPa
• Ta>5˚C
• LP<0.049MPa
• Ta≤5˚C
H Malfunction reset
LP>0.09MPa
LP>0.10MPa
(Monitoring LP every 30 sec.)
LP>0.07MPa
(Monitoring LP every 1 min)
Ta : Outdoor air temp. (˚C)
Tes : Low pressure equivalent
saturation temp. (˚C)
[Heating mode]
[Cooling mode]
SVP (for hot
gas bypass) : ON
LP > 0.13 MPa
Upper limit frequency =
Maximum frequency
1-step increase for
compressor
operation frequency
[Oil return mode (common for cooling / heating)]
Restriction for upper limit
compressor operation
frequency H 1
(V0822)