Basic Documentation

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Siemens Modular Heating Controller RMH760B CE1P3133en
Building Technologies 10 DHW heating 2017-09-29
From the limit value, pulse limitation starts throttling the actuating device (mixing valve).
The setting is only active when the limitation is absolute. In the case of scaled
limitation, the limit value can be set, but the function works with 75 pulses/min (fixed
value).
The setting value determines the rate at which the flow temperature setpoint will be
lowered:
• Short integral action times lead to a faster reduction
• Long integral action times lead to a slower reduction
10.8.5 Pump overrun and mixing valve overrun
To protect the boiler against overtemperatures on burner shutdown because there may
be no more consumers drawing heat, a consumer overrun time can be set on the boiler
controller.
When the burner has shut down, overrun ensures that the heating circuits and DHW
heating will still draw a certain amount of heat during that period of time, provided they
were consuming heat up to one minute before shutdown occurred. In any case, pumps
and mixing valves have an overrun time of 60 seconds.
For more detailed information, refer to section 5.4 "Pump overrun and mixing valve
overrun".
In the case of direct DHW heating, overrun is not possible since there is no pump on
het secondary side. Overrun does not act on the circulating pump.
Overrun applies to both the primary and the secondary pump.
To carry the residual heat away from the heat exchanger, plant types DHW 4 and DHW
5 (with heat exchanger and primary pump) offer a setting for an additional overrun time
of the secondary pump:
Main menu > Settings > DHW > Controller primary circuit
Operating line
Range
Factory setting
Overrun time secondary pump
0…60 min
1 min
10.8.6 Pump kick and valve kick
Pump kick and valve kick are protective functions that are performed at a certain interval.
They prevent pumps and / or actuators from seizing after longer off periods.
10.9 Heat demand
DHW heating sends its heat demand as a temperature request to the heat source.
The temperature request for the current heat demand of DHW heating is dependent on
the plant type and calculated as follows:
Plant type
Temperature request
DHW 0
DHW heating works autonomously, that is, independent of heat
generation. No temperature request will be delivered
DHW 1
Storage tank temperature setpoint + setpoint increase DHW charging
DHW 2
Storage tank temperature setpoint + setpoint increase heat exchanger
+ setpoint increase mixing valve
DHW 3
Storage tank temperature setpoint + setpoint increase heat exchanger
DHW 4
Storage tank temperature setpoint + setpoint increase heat exchanger
+ setpoint increase mixing valve
DHW 5
Storage tank temperature setpoint + setpoint increase heat exchanger
DHW 6
DHW temperature setpoint + setpoint increase heat exchanger
Limit value
Integral action time (Tn)
Consumer overrun
Direct DHW heating
Primary pump
and
secondary pump