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128
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Service
'10 • HM-T-149
Upper / Lower limit of the supply water temperature
Regardless of the heating curve setting and the outdoor air temperature, target water temperature cannot exceed the min/max supply
water temperature set in Menu 2.1.4 and 2.3 for heating system 1 or in Menu 3.3 and 3.4 for heating system 2.
Upper and lower limit is set after various offset correction.
For example, when the upper and lower limit is set as below mentioned gure, and if heating curve A and B is selected, target supply
water temperature is shown in full line and dotted line respectively.
Outdoor air temperature (°C)
Calculated supply temp (°C)
Max supply temp in Menu 2.3
(Menu 3.4 for system2)
Heating curve A
Min supply heating in Menu 2.1.4
(Menu 3.3for system2)
Heating curve B
Water temperature control when deviated from the target
When the DM value is signicantly small, supply water temperature must be controlled higher than target temperature to reduce the
decit of DM value. However, too big overshoot of the supply temperature will affect comfort.
In order to control the supply water temperature to avoid uctuation of room temperature, overshoot limit is set in Menu 9.6.7 (Max
diff flow-cFlow). Once the supply water temperature reaches the threshold of Menu 9.6.7, thereafter the compressor speed is
controlled so that the supply water temperature is kept below the overshoot limit.
For details, see the timing chart on page 134.
Operation control function by the indoor unit controller