Daikin R407C PLUS Service Manual page 85

Outline of Control (Outdoor Unit) < Symbols using in this manual >
3.5.2 Low Pressure Protection Control
The following control is provided to protect the compressors from abnormal decrease of low
pressure (LP).
[Cooling mode]
LP<0.15MPa
Normal operation
•
LP>0.20MPa
•
&
•
30 sec elapse
OR
•
Ta<Tes+5
[Heating mode]
LP<0.08MPa
Normal operation
0
SVP : OFF
LP > 0.13 MPa
Upper limit frequency =
Maximum frequency
[Oil return mode (common for cooling / heating)]
"
74
•
LP<0.08MPa
•
&
•
Ta>5˚C
OR
•
LP<0.049MPa
•
&
•
Ta≤5˚C
Compressor
operation
frequency
31Hz+OFF+OFF
•
LP>0.13MPa
•
& •
Ta>5˚C
OR
•
LP<0.098MPa
•
&
•
Ta≤5˚C
LP<0.05MPa
Restriction for upper limit
SVP (for hot
compressor operation
gas bypass) : ON
frequency
1-step increase for
compressor
operation frequency
LP<0.05MPa
SVP (for hot gas
bypass) : OFF
LP>0.10MPa
1.Upper limit compressor operation : According to "Drooping step Table". See next page.
Ta : Outdoor air temp. (˚C)
SVP (for hot gas
Tes : Low pressure equivalent
bypass) : ON
LP<0.03MPa
Forced thermostat
OFF
0
1
LP>0.10MPa
(Monitoring LP every 30 sec.)
LP>0.07MPa
(Monitoring LP every 1 min)
SVP (for hot gas
bypass) : ON
Function R407C PLUS Series Heat Recovery System
saturation temp. (˚C)
LP<0.0MPa
E4 malfunction
stop
0
Malfunction reset
LP>0.09MPa
Si33-105
(V0822)