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Outline of Control (Outdoor Unit) < Symbols using in this manual >
SiE33-105
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]
OR
LP<0.15MPa
OR
•&
Compressor
operation
frequency
31Hz+OFF+OFF
Normal operation
•&
•&
• LP>0.20MPa
• 30 sec elapse
• Ta<Tes+5
• LP<0.08MPa
• Ta>5˚C
• LP<0.049MPa
• Ta≤5˚C
SVP (for hot gas
bypass) : ON
Ta : Outdoor air temp. (˚C)
Tes : Low pressure equivalent
saturation temp. (˚C)
• LP>0.13MPa
• & • Ta>5˚C
OR
• LP<0.098MPa
•&
• Ta≤5˚C
[Heating mode]
LP<0.08MPa
Normal operation
SVP : OFF
0
LP<0.05MPa
SVP (for hot
gas bypass) : ON
LP<0.03MPa
Restriction for upper limit
compressor operation
frequency 1
0
Forced thermostat
OFF
LP>0.10MPa
(Monitoring LP every 30 sec.)
LP>0.07MPa
(Monitoring LP every 1 min)
LP > 0.13 MPa
Upper limit frequency =
Maximum frequency
LP<0.0MPa
E4 malfunction
stop
0 Malfunction reset
LP>0.09MPa
1-step increase for
compressor
operation frequency
[Oil return mode (common for cooling / heating)]
LP<0.05MPa
SVP (for hot gas
bypass) : OFF
SVP (for hot gas
bypass) : ON
LP>0.10MPa
(V0822)
1.Upper limit compressor operation : According to “Drooping step Table”. See next page.
74
Function R-407C PLUS Series Heat Recovery System