133/226
Building Technologies
Boiler Sequence Controller RMK770
CE1P3132en
HVAC Products
8 Heat demand and heat requisitions
01.03.2005
T
T
T
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RMH760
3131B
05
Room unit
(in reference room)
Central
air handling
DHW
precontrol
Chilled water
precontrol
Air supply area
RMH760
RMU...
0...100 %
3131B
06
Precontrol
heating
Ventilation
Precontrol
refrigeration
Heat demand
transformer
Refrigeration
demand
transformer
Based on the valve position of the air handling plant(s), the heat demand transformers
calculate a flow temperature setpoint.
If an outside temperature signal is available on the primary controller, the flow tempera-
ture setpoint according to the heating curve will be used as a start value. If there is no
outside temperature signal, the flow temperature at curvepoint 1 is used as the stat
value.
This flow temperature start value is matched to the actual heat demand in a way that
the heat consumer with the greatest heat demand has a valve position of 90 %.
•
If the valve position is >90 %, the flow temperature will be increased
•
If the valve position is <90 %, the flow temperature will be decreased
The maximum flow temperature readjustment can be parameterized.
To ensure that minimum opening travel of the valve will not produce a demand for heat,
a switch-off threshold can be defined.
•
Demand for heat is computed only if the valve positions exceed “Threshold on”
•
If the valve positions of all consumers are below “Threshold off“, the demand for heat
will be suppressed again
Main menu > Settings > Inputs > Demand control
Operating line
Range
Factory setting
[Curvepoint 1] outside temp
–50…50 °C
–10 °C
[Curvepoint 1] flow temp
0…140 °C
70 °C
[Curvepoint 2] outside temp
–50…50 °C
20 °C
[Curvepoint 2] flow temp
0…140 °C
70 °C
Flow temp correction max
0…100 K
10 K
Control action
Slow / Medium / Fast
Medium
Requisition evaluation
Maximum / Average
Maximum
Limit value requisition on
(Threshold off)…100 %
10 %
Limit value requisition off
0…(threshold on)
5 %
Example:
Air handling plant