Mitsubishi Heavy Industries FDT71VNXVD Service Manual page 16

(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] 1) Starts with the compressor's target frequency at A rps.
(b) Compressor protection start III
[Control condition] Number of compressor starts is only 1 counted after the power supply breaker ON.
[Control contents]
1) Low frequency operation control during cooling/dehumidifying
[Control condition] Upon establishing the conditions of compressor protection start III, the low frequency
[Control contents]
2) Low frequency operation control during heating
[Control condition] When the conditions of compressor protection start III are established and one of following conditions
[Control contents]
However, when the ambient air temperature (Tho-A) is 35°C or higher during cooling/
dehumidifying or the indoor return air temperature (Th
starts at C rps.
2) 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 Operation mode
Cooling/Dehumidifying
71
Heating
Cooling/Dehumidifying
100
Heating
Cooling/Dehumidifying
125, 140
Heating
Operates by selecting one of following start patterns according to the operation mode and the
outdoor air temperature (Tho-A).
operation control is performed during cooling/dehumidifying.
a) 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.
b) 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 Operation mode
71 Cooling/Dehumidifying
100 Cooling/Dehumidifying
125, 140 Cooling/Dehumidifying
a) and b) is satisfied, the low number of revolutions operation control is performed during heating.
a) At 30 minutes or more after turning the power supply breaker on
b) Compressor underneath temperature (Tho-H) is 4°C or higher and the difference from the
outdoor air temperature (Tho-A) becomes 4°C or higher. [model 200, 250 only]
a) Starts the compressor with its target frequency at A rps. However, when the indoor unit
return air temperature (Th
b) 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 Operation mode
71
100
125, 140
-
-A) is 25°C or higher during heating, it
I
A rps
42
62
55
55
45
45
A
rps
42
55
45
-A) is 25°C or higher, it start at C rps.
I
A
rps
42
Heating
55
Heating
45
Heating
-
21
'10 • PAC-SM-137A
B rps C rps
42 40
62 40
55 30
55 30
45 25
45 25
B C
rps rps
42 40
55 30
45 25
B C
rps rps
42 40
55 30
45 25