Modulating Pump; Modulation Of Heating Circuit Pump - Siemens LMS14 User Manual

Operating level
Heating curve
Weather-compensated
Additional parameters
Info/diagnostics
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Building Technologies Division

6.39 Modulating pump

6.39.1 Modulation of heating circuit pump

The speed of the heating circuit pump can be calculated in accordance with Operating
level, Characteristic, or Temp differential nominal.
The selection is made via parameters Pump speed reduction (880/1180/1480) for
heating circuits 1 to 3.
When using option Operating level, the speed of the heating circuit pump is calculated
based on the current operating level. In the case of operating level Reduced, the pump
is controlled to the parameterized minimum. In the case of operating level Comfort and
activated floor curing function, the pump is controlled to the parameterized maximum.
When using option Heating curve, the speed of the heating circuit pump is calculated
based on the selected compensation variant (weather- or room-compensated).
With compensation variant Weather-compensated (with or without room influence), the
speed of the heating circuit pump is maintained at the parameterized minimum as long
as the heating demand can be satisfied. To be able to also meet the heat demand with
reduced speed, the flow temperature must be increased. The flow temperature increase
can be parameterized.
Parameter Curve readj at 50% speed (888) defines the flow temperature increase in
percent when the pump speed is reduced by 50%.
The speed of the heating circuit pump is calculated based on the flow temperature
currently obtained and the current flow temperature setpoint. The actual value of the
common flow temperature is used as the actual value. If no common flow sensor is
installed, the actual value of the boiler flow is used. It is attenuated with a filter, the time
constant can be parameterized (Filter time const speed ctrl (889)).
(Example heating circuit 1)
Line no. Operating line
880
Pump speed reduction
881 Starting speed
882 Pump speed min
883 Pump speed max
885 Pump speed min OEM
886 Pump speed max OEM
888 Curve readj at 50% speed
889 Filter time const speed ctrl
890 Flow setp readj speed ctrl
[4291.1] Delay speed ctrl HC1
Line no. Operating line
8308 Boiler pump speed
8310 Boiler temp
8735 Speed heating circuit pump 1
8765 Speed heating circuit pump 2
8795 Speed heating circuit pump 3
User Manual LMS14...
6 The settings in detail
CC1U7471en
28.01.2015