Mitsubishi Electric PQHY-P72TYHMU-A Service Handbook page 157

[ VII Control ]
-10- Capacity Control of Heat Exchanger<PQRY>
(1) Control method
ŒDepending on the capacity required, the rotation speed of the heat source unit fan is controlled by the inverter to keep a con-
stant condensing temperature of (water temperature +10°C [50°F]) during cooling operation and a constant evaporation tem-
perature of (0°C [32°F] =0.71 <Pa [103psi]) during heating operation.
ŒThe OS in the multiple-heat source-unit system operates at the actual heat source unit fan control value that is calculated by
the OS based on the preliminary heat source unit fan control value that the OC determines.
(2) Heat source unit heat exchanger capacity control patterns
Model
P72 - P120 models Cooling-main
Cooling-only
Cooling-main
Heating-only
Heating-main
HWE09080
Operation Operation
mode pattern
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
- 148 -
Solenoid valve
SV4a SV4b SV4d
ON OFF ON
ON OFF ON
ON OFF ON
ON OFF ON
ON ON ON
ON ON ON
ON ON ON
ON ON ON
ON OFF OFF
ON OFF OFF
ON OFF OFF
ON OFF OFF
ON ON OFF
ON ON OFF
ON ON OFF
ON ON OFF
ON OFF ON
ON OFF ON
ON OFF ON
ON OFF ON
ON ON ON
ON ON ON
ON ON ON
ON ON ON
ON OFF OFF
ON OFF OFF
ON OFF OFF
ON ON OFF
ON ON OFF
ON ON OFF
ON ON OFF
SV7a SV7b
ON ON
OFF ON
ON OFF
OFF OFF
ON ON
OFF ON
ON OFF
OFF OFF
ON ON
OFF ON
ON OFF
OFF OFF
ON ON
OFF ON
ON OFF
OFF OFF
ON ON
OFF ON
ON OFF
OFF OFF
ON ON
OFF ON
ON OFF
OFF OFF
ON ON
OFF ON
ON OFF
ON ON
OFF ON
ON OFF
OFF OFF
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