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Additional parameters
Additional parameters
Info/diagnostics
572/617
Building Technologies Division
6.39.4 Conditions for limiting the boiler's temperature differential
Limitation of the boiler's temperature differential is possible only if a valid value of the
boiler return temperature is available.
Another prerequisite is a valid value of Temp differential max (2316), which means that
it must not be an OSV.
Limitation of the boiler's temperature differential is only effective in connection with pure
space heating. As soon as a DHW request becomes active, limitation of the boiler's
temperature differential is suppressed.
In Heating mode, the limitation is effective only if a request from the heating circuit with
modulating pump is active.
Limitation of the boiler's temperature differential also remains effective when additional
requests from other heating circuits are pending.
In the case of systems with modulating boiler pump, limitation of the boiler's
temperature differential depends on the assignment of the boiler pump (Ctrl boiler
pump/DHW valve) (5774). If the boiler pump is assigned to heating circuit 1 only,
limitation becomes active when there is a request for heat from heating circuit 1. If the
boiler pump is assigned to all heating circuits, limitation becomes active as soon as any
of the heating circuits calls for heat.
Line no.
Operating line
2316
Temp differential max
5774
Ctrl boiler pump/DHW valve
6085
Function output P1
6.39.5
Limitation dependent on pump modulation
Limitation of the boiler's temperature differential is dependent on the current modulation
of the heating circuit pump. Depending on the current degree of modulation, different
preselected values are used for limiting the boiler's temperature differential.
As long as the modulating heating circuit pump is not controlled to the maximum speed,
the parameterized nominal boiler temperature differential is used for limiting the boiler
temperature increase. If there is a deficit in the supply of heat to the heating circuit, this
can be compensated for via speed control by increasing pump modulation.
The parameterized maximum value Temp differential max for the boiler's temperature
differential applies only when the modulating heating circuit pump is controlled with
maximum PWM (maximum pump speed heating circuit x.
Line no.
Operating line
2316
Temp differential max
Line no.
Operating line
8314
Boiler return temp
User Manual LMS14...
6 The settings in detail
CC1U7471en
28.01.2015
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