Panasonic Urban Multi MX1R Series Service Manual page 458

PACD011001C2
3.1.11 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
LP > 0.13 MPa
Upper limit frequency =
Maximum frequency
[Oil return mode (common for cooling / heating)]
Function UM Combination "MA1R Series" Using R-407C
·LP<0.08MPa
·&
·Ta>5˚C
OR
·LP<0.049MPa
·&
·Ta≤5˚C
Compressor
SVP (for hot gas
operation
bypass) : ON
frequency
31Hz+OFF+OFF
·LP>0.13MPa
·&
·Ta>5˚C
OR
·LP<0.098MPa
·&
·Ta≤5˚C
LP<0.05MPa
Restriction for upper
SVP (for hot
limit compressor
gas bypass) : ON
operation frequency ∗1
1-step increase for
compressor
operation frequency
LP<0.05MPa
SVP (for hot gas SVP (for hot gas
bypass) : OFF bypass) : ON
LP>0.10MPa
Ta : Outdoor air temp. (˚C)
Tes : Low pressure equivalent
saturation temp. (˚C)
LP<0.03MPa
Forced thermostat
OFF
LP>0.10MPa
(Monitoring LP every 30 sec.)
LP>0.07MPa
(Monitoring LP every 1 min)
Outline of Control
LP<0.0MPa
E4 malfunction
stop
∗ Malfunction reset
LP>0.09MPa
(V0822)
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