Automatic Heat Generation Lock; Manual Heat Generation Lock - Siemens LMS14 User Manual

Building Technologies Division
6.12.3

Automatic heat generation lock

This function can be activated by the buffer storage tank (sensor B4/B41). The boiler is
locked by the automatic heat generation lock when all valid requests for heat can be
satisfied by the buffer storage tank and when the respective heat consumers are
hydraulically connected with the buffer storage tank.
Requests for heat from heat consumers not hydraulically connected with the buffer
storage tank lead to a release of the boiler, even if the buffer storage tank holds
sufficient amounts of heat.
Each consumer segment can have its own buffer storage tank. Hence, the automatic
heat generation lock can be parameterized per segment (refer to chapter Buffer storage
tank).
If the boiler is disabled by automatic heat generation lock while the burner is running,
the burner is shut down, either immediately or only when the set minimum boiler
temperature is reached, depending on the parameterization.
6.12.4

Manual heat generation lock

An active manual heat generation lock disables the boiler, independent of current
requests for heat.
When there is an external request for heat, manual heat generation lock does not
disable the boiler.
For that purpose, one of the input contacts Hx, which can be parameterized, can be
used.

Protective boiler startup in progress with a boiler switch-off point at the minimum
boiler temperature is completed

Maintained boiler return temperature acting on the consumers and shifting DHW
priority is aborted

Boiler pump is deactivated on completion of the overrun time

Frost protection for the boiler continues to be active
When setting the parameters, the Heat generation lock function must be selected for
the respective input Hx. The type of contact can be parameterized also (NC or NO).
With certain hydraulic configurations, it may be necessary to exclude the boiler pump
from the Locking function when the heat generation lock is active. This applies
particularly to configurations where a buffer storage tank is available as a heat source.
In that case, parameter Boiler pump on heat gen lock (2301) must be set to On.
User Manual LMS14...
6 The settings in detail
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CC1U7471en
28.01.2015