136/232
Building Technologies Boiler Sequence Controller RMK770 CE1P3132en
HVAC Products 8 Heat demand and heat requests 23.04.2009
The heat demand transformer converts the position heat request signals (in %) to heat
demand signals with a flow temperature setpoint.
The following example of an air handling plant shows this.
T
T
T
T
RMH760
3131B05
Room unit
(in reference room)
Central
air handling
DHW
precontrol
Chilled water
precontrol
Air supply area
RMH760
RMU...
0...100 %
3131B06
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 is 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 is increased
• If the valve position is <90%, the flow temperature is decreased
The maximum flow temperature readjustment can be parameterized.
To ensure that minimum opening travel of the valve does 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
is suppressed again
Main menu > Commissioning > Settings > … or
Main menu > Settings > Boiler sequence manager > Demand control
Main menu > Settings > Primary controller > 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
Request evaluation Maximum / Average Maximum
Limit value request on
(Threshold off)…100%
10 %
Limit value request off 0…(threshold on)
5 %
Example:
ir handling plant
To Next Page
Loading...
