Outline of Control PACD011001C2
438 Function UM Combination “MA1R Series” Using R-407C
3.1.12 High Pressure Protection Control
The following control is provided for the compressor operating frequency and others to prevent protection
devices from malfunctioning due to abnormal increase of high pressure (HP) and to protect the
compressors.
[Cooling mode]
[Heating mode]
Condition (1)
Condition (2) (During soft start)
Condition (3)
Condition (4)
OR
&
Indoor unit thermostat ON capacity of 8.0 kW (3HP) or less
OR
&
Ta
≥
15°C
HP
≥
2.16MPa
&
Ta < 15°C
HP
≥
2.25MPa
HP
≥
2.37MPa
OR
&
Indoor unit thermostat ON capacity of 8.0 kW (3HP) or less
OR
Ta
≥
15°C
&
Ta < 15°C
HP
≥
2.26MPa
HP
≥
2.37MPa
&
OR
HP < 1.70MPa
Continues for 300 sec
HP < 1.54MPa
5 min elapsed after compressor startup
5 min elapsed after defrost completion
5 min elapsed after oil return completion
&
HP > 2.37MPa
5 min elapsed after defrost completion
5 min elapsed after oil return completion
Normal
operation
1 step down for upper limit
compressor operation frequency
*Judge every 10 sec, and down
1 step until HP<2.55 MPa
1 step increase for compressor
operation frequency
Forced
thermostat OFF
E3 normal
stop
HP ≥ 2.55 MPa
Retry
HP ≥ 2.81 MPa
HP < 2.55 MPa
HP > 3.09 MPa
HP < 2.26 MPa
Continues 30 sec.
HP < 2.50 MPa
Continues 5 min.
(V0823)
Up to 2 times
within 30 min
&
• Heating operation
• Compressor stop
• Upper limit frequency
becomes maximum
OR
&
OR
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