Maximum Limitation Of The Boiler Temperature; Minimum Limitation Of The Boiler Temperature; Optimization Of Minimum Boiler Temperature - Siemens Synco 700 Basic Documentation

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6.6.1

Maximum limitation of the boiler temperature

This setting is used to provide maximum limitation of the boiler temperature setpoint.
For control of the burner, this value represents the switch-off point. In this range, the
boiler's switching differential downward is calculated.
Maximum limitation of the boiler temperature is always active. The only exception is the
wiring test.
TBo
80
70
60
50
40
30 0
20 10
HD Heat demand
SDB0
Boiler's switching differential
TBo Boiler temperature
TBoMax
Maximum limit of the boiler temperature
TBoMin Minimum limit of the boiler temperature
TBoSetpt Boiler temperature setpoint
6.6.2

Minimum limitation of the boiler temperature

This setting is used to provide minimum limitation of the boiler temperature. For control
of the burner, this value represents the switch-on point. In this range, the boiler's
switching differential upward is calculated.
Maintenance of the minimum boiler temperature is dependent on the boiler shutdown
setting (see below).
When there is a heat request, the minimum boiler temperature is always active.
If a minimum return temperature is required, it must be ensured that the minimum boiler
temperature will be set to a level which lies a few K above the minimum return tempera-
ture.
6.6.3

Optimization of minimum boiler temperature

If optimization of the minimum boiler temperature is set to On , the control system will
select the switch-on point such that, normally, the boiler temperature will not drop below
the minimum. Using this function, a load-dependent forward shift of the burner's switch-
on point can be achieved. In that case, the minimum boiler temperature need not be
determined with an unnecessarily great safety factor since with large loads, the burner
switches on earlier and, with small loads, later. Hence, the range in which the boiler
temperature can be shifted can be widened.
Based on the boiler temperature gradient, the controller calculates the burner's switch-
on point to ensure that the boiler temperature will not drop below the minimum.
When the function is deactivated, the controller switches the burner on at the minimum
boiler temperature TBoMin.
Modular Heating Controller RMH760B
6 Boiler temperature control
TBoMax
TBoSetpt
TBoMin
0 -10
SDBo
-20 °C HD
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