Mitsubishi Electric CAHV-P500YB-HPB, Service Handbook

Page: 105 / 169

[
VII
Control ]
- 98 -
HWE15070 GB
Cooling/heating Circuit Control and General Function of System Equipment
-13- Water-temperature control
Water temperature can be controlled in the following three ways. Select one that works best.
*1 When dip switch SW2-8 is set to ON, the ON/OFF operation of the units is controlled based on the external water
temperature sensor reading.
How the operating frequency of the compressor is controlled depends on the SW3-3 setting (outlet-/inlet-based control
option).
(Sub units will be controlled based on the water-temperature control method that has been selected for the Main unit.)
1. When the units are restarted after stopping for under a condition other than Thermo-OFF
Conditions for the units to stop other than the Thermo-OFF condition
 The control option was changed from built-in thermistor reading based control to the external thermistor reading based
control.
 Pump interlock is off.
 When one of the units in a set is forced to stop
 When the Capacity priority/Cop priority setting was changed.
 When the units were stopped under the following conditions:
1. Tmax has reached 65ºC (when the outside temperature ≤ -10ºC) or
2. Tmax has reached 70ºC (when the outside temperature > -10ºC.
DIFF1 = 2 ºC (Initial setting): “1015” Digitally set value
DIFF2 = 2 ºC (Initial setting): “1016” Digitally set value
Tmax (Outside temperature
≤
-10 ºC: 65ºC, Outside temperature > -10 ºC : 70ºC)
Switch Factory setting
Outlet-water-temperature-based control
SW3-3
OFF
Inlet-water-temperature-based control -
Water temperature control based on the
external water temperature reading
SW2-8 OFF
SW3-3 SW2-8
Outlet-water-temperature-based control OFF OFF
Inlet-water-temperature-based control ON OFF
Water temperature control based on the
external water temperature reading
Arbitrary
*1
ON
Single/Multiple system sensor Control method Thermo-ON conditions
Individual system
Built-in thermistor
Inlet-water-tempera-
ture-based control
Outlet water temperatures
< (Preset water temperature - DIFF1ºC)
AND
Inlet water temperatures
< (Preset water temperature - DIFF1ºC)
Outlet-water-temper-
ature-based control
Outlet water temperatures
< (Preset water temperature - DIFF1ºC)
AND
Inlet water temperatures
< (Preset water temperature - DIFF1ºC)
AND
Average outlet water temperature
≤ (Preset water temp DIFF2ºC)
Representative water
temperature
Representative water
temperature
Representative water temperature
< (Preset water temperature - DIFF1ºC)
Multiple system
Representative water
temperature
Representative water
temperature
Representative water temperature
< (Preset water temperature - DIFF2/2)
AND
The number of units to run an optimal opera-
tion will be determined by the main unit.
(The unit with the least amount of cumulative
operation hours will go into operation first.)
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