Basic Documentation

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Siemens Modular Heating Controller RMH760B CE1P3133en
Building Technologies 6 Boiler temperature control 2017-09-29
correctly acquired, it must be made certain that the maintained boiler return
temperature will have no impact on DHW heating. Also, the maintained boiler return
temperature must not act on the main pump if the return temperature is only correctly
acquired when the main pump runs.
In the case of a boiler with bypass pump (boiler pump parallel to the boiler), maintained
boiler return temperature can be ensured by activating the bypass pump.
3133S72
TBo
ByPu
TRtBo
The bypass pump can be controlled either according to the acquired return temperature
or, when there is no sensor, parallel to burner operation.
Normally, the return temperature sensor is installed upstream of the bypass pump (on
the consumer side) to avoid too frequent switching of the bypass pump.
Main menu > Commissioning > Settings > … or
Main menu > Settings > Boiler > Limitations
Operating line
Range
Factory setting
Bypass pump switching diff
0…20 K
6 K
The return temperature is controlled with the bypass pump in 2-position mode within
the adjustable switching differential.
The pump will be activated when there is demand for heat and when the return
temperature drops below its minimum limit value.
The pump will be deactivated when the return temperature exceeds its minimum limit
value by the switching differential, or when there is no demand for heat.
Br
ByP
TiOverrunCnsm
TBoR
t [min]
10 20 30
60
50
40
30
TBoRmin+SDByP
TBo
TBoRmin
0
1
t
0
1
t
3131D05
Br
Burner
ByP
Bypass pump
SDByP
Switching differential of bypass pump
t
Time
TBo
Boiler temperature
TBoR
Boiler return temperature
TBoRmin
Minimum limit value of the boiler return temperature
TiOverrunCnsm
Consumer overrun time
Maintained boiler return
temperature with bypass
pump