Compressor Start Control; Compressor Soft Start Control - Mitsubishi Heavy Industries V Multi FDC71VNX Technical Manual

(2) Compressor start control

(a) Compressor starts upon receipt of the thermostat ON signal from the indoor unit.
(b) However, at initial start after turning the power source breaker, it may enter the standby state for maximum 30 minutes
(" PREPARATION" is displayed on the remote control) in order to prevent the oil loss in the compressor.
If the cooling/dehumidifying/heating operation is selected from the remote control when the outdoor unit is in the
standby state, " PREPARATION" is displayed for 3 seconds on the remote control.

(3) Compressor soft start control

(a) Compressor protection start I
[Control condition]
Normally, the compressor operation frequency is raised in this start pattern.
[Control contents]
a) Starts with the compressor's target frequency at A rps.
However, when the ambient air temperature (Tho-A) is 35°C or higher during cooling/dehumidifying or the indoor
return air temperature (Thi-A) is 25°C or higher during heating, it starts at C rps.
b) At 30 seconds after the start of compressor, its target frequency changes to B rps and the compressor is operated for
2 - 4 minutes with its operation frequency fixed at B rps.
Model
100-140
(b) Compressor protection start III
[Control condition]
Number of compressor starts is only 1 counted after the power source breaker ON.
[Control contents]
Operates by selecting one of following start patterns according to the operation mode and the outdoor air
temperature (Tho-A).
i) Low frequency operation control during cooling/dehumidifying
[Control condition]
Upon establishing the conditions of compressor protection start III, the low frequency operation control is
performed during cooling/dehumidifying.
[Control contents]
➀ Starts with the compressor's target frequency at A rps. When the outdoor air temperature (Tho-A) is 35°C or
higher, it starts at C rps.
➁ At 30 seconds after the compressor start, the compressor's target frequency is changed to B rps and the
compressor's operation frequency is fixed for 10 minutes.
Model
100-140
ii) Low frequency operation control during heating
[Control condition]
When the conditions of compressor protection start III are established and the following condition is satisfied, the low
number of revolutions operation control is performed during heating.
➀ At 30 minutes or more after turning the power source breaker on
[Control contents]
➀ Starts the compressor with its target frequency at A rps. However, when the indoor unit return air temperature
(Thi-A) is 25°C or higher, it start at C rps.
➁ At 30 seconds after the start of compressor, the compressor's target frequency is changed to B rps and the
compressor's operation frequency is fixed for 10 minutes.
Model
100-140
Operation mode
Cooling/Dehumidifying
Heating
Operation mode
Cooling/Dehumidifying
Operation mode
Heating
A rps B rps
55 55
55 55
A rps B rps
55 55
A rps B rps
55 55
326
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'19 • PAC-T-327
C rps
30
30
C rps
30
C rps
30