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Additional parameters
216/617
Building Technologies Division
Temp differential nominal
The objective of this function is to modulate the speed of the boiler pump such that the
boiler temperature increase is maintained at the level of the parameterized nominal
increase (Temp differential nominal (2317)). The boiler temperature increase is the
difference of return temperature (sensor B7) and flow temperature (sensor B2). If the
current boiler temperature increase is greater than the nominal increase, speed control
responds by increasing the pump speed and, on the other hand, by reducing the pump
speed.
The pump's speed is controlled by a PID controller based on the control coefficients for
the boiler pump (Speed Xp (2324), Speed Tn (2325), and Speed Tv (2326)).
Limitation of the pump speed results from the minimum and maximum speed
parameterized for the boiler pump.
In DHW heating operation, control of the boiler pump speed is not effected according to
the parameterized boiler temperature increase. Here, the speed of the boiler pump is
calculated based on the Demand function (see above).
For all other operating modes – with the exception of DHW heating – following applies:
If the boiler return temperature is not available (sensor faulty or not configured), or if no
valid nominal boiler temperature increase is configured, the speed of the boiler pump is
calculated based on the Boiler setpoint function.
Line no.
Operating line
2324
Speed Xp
2325
Speed Tn
2326
Speed Tv
User Manual LMS14...
6 The settings in detail
CC1U7471en
07.05.2014
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