Siemens LMS14 User Manual

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Building Technologies Division User Manual LMS14… CC1U7471en
6 The settings in detail 28.01.2015
6.12 Special boiler functions
6.12.1 Change of operating mode
When there is a change between space heating and DHW heating, the controller
responds as follows:
 DHW heating is ended and, at the same time, there is a request from space
heating:
The controller switches the burner off. DHW overrun is performed while the position
of the DHW controlling element is maintained
 The request from space heating is overridden by a DHW request:
The controller adopts the new DHW setpoint and makes use of the DHW
thresholds. The DHW controlling element switches over to DHW heating. The
controller switches off the burner only if the DHW switch-off threshold is or will be
exceeded when changing from heating circuit to DHW operation mode. In general,
however, the DHW setpoint lies above the setpoint for the heating circuit so that
shutdown will not take place
6.12.2 Loading the setpoint/actual value
Depending on the operating mode, the respective setpoints/actual values are loaded to
the LMS14....
Heating mode DHW storage tank
charging
Instantaneous
water heating
Setpoint Boiler temperature
setpoint
Boiler temperature
setpoint/DHW
charging setpoint
TwwSoll
Actual value Actual value of
boiler temperature
Actual value of
boiler temperature/
DHW charging
temperature
TwwIst1/TRueck/
actual value of
boiler temperature
Key
Line no. Meaning
TwwIst1 Sensor B38 at outlet of instantaneous water heater
TwwSoll Setpoint DHW outlet/keep hot setpoint
TRueck Boiler return temperature
In the case of instantaneous water heaters, the DHW setpoint is used. Depending on
the configured type of instantaneous water heater, the respective actual value is
loaded. With instantaneous water heaters, this is dependent on the type of hydraulic
system, Outlet or Comfort mode and parameterization.

Siemens LMS14 Specifications

General

Brand	Siemens
Model	LMS14
Category	Control Unit
Language	English