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Pump modulation
Additional parameters
214/617
Building Technologies Division
6.11.14 Speed control
To calculate modulation of a speed-controlled boiler pump, several functions are
available. The required function can be selected via parameter Pump modulation
(2320).
Line no.
Operating line
2320
Pump modulation
None
Demand
Boiler setpoint
Temp differential nominal
Burner output
None
No speed is selected for the boiler pump. The output delivers 0% PWM.
Demand
The speed of the boiler pump is calculated based on the speed requests from the
consumers. Calculation of the speed is dependent on the consumers in the plant, the
currently valid heat requests, and the pump speeds calculated by the individual
consumers.
Only consumers acting on the same controller are considered.
When there is a request for DHW heating, the speed calculated for the DHW pump
(charging pump Q3 or instantaneous water heater pump Q34) is used for the boiler
pump. The speed limits of the DHW pump apply.
If there is no request for DHW heating, the pump speed is calculated based on the
speed requests from the heating circuits. The speed of the boiler pump results from the
highest pump speed calculated by the heating circuits. The pump speed calculated by
heating circuits 2 and 3 is evaluated only if these heating circuits are hydraulically
dependent on the position of the diverting valve (Ctrl boiler pump/DHW valve (5774))
and thus on the boiler pump.
The speed of the DHW or heating circuit pump is also used for the boiler pump. Hence,
only the speed limits of the DHW pump or the respective heating circuit pump apply. In
this case, the speed limits parameterized for the boiler pump are not considered.
Line no.
Operating line
5774
Ctrl boiler pump/DHW valve
Note!
This function is only for use with single-boiler plants.
For cascaded systems, one of the other functions must be selected.
User Manual LMS14...
6 The settings in detail
CC1U7471en
07.05.2014
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