Overtemperature Protection - Siemens LMS14 User Manual

SD burner off time
Release of minimum off
time
Start of minimum
off time
Interruption of
minimum off time
End of minimum off time
Pump overrun time
Pump overr time after
DHW
206/617
Building Technologies Division
Line no. Operating line
2245 SD burner off time
If SD burner off time is exceeded, the minimum off time is aborted.
If a request for heat puts the burner into operation, the minimum off time is enabled,
which means that it will commence the next time the 2-position controller or the limit
thermostat initiates shutdown.
In the event of shutdown initiated by the 2-position controller or limit thermostat, the
minimum off time commences if previously enabled.
If one of the following requests is received during the minimum off time, it is
immediately processed:

DHW request

Frost protection for the boiler

Controller stop function

Chimney sweep function
The minimum off time for heat requests continues to elapse in the background.
Requests for heat cause the burner to restart when...

the minimum off time has elapsed,

the parameterized control deviation (SD burner off time) is exceeded.

6.11.8 Overtemperature protection

If the burner shuts down or if the request for heat becomes invalid, a forced overrun
signal is forwarded during the parameterized pump overrun time. If such a signal is
received, consumer groups must not be shut down. During the time the forced signal is
active, the mixing valve setpoint for flow temperature control is maintained at the former
setpoint. If the last pending heat request was received from a DHW component
(instantaneous water heater or storage tank), the overrun parameter for DHW heating is
used for boiler pump Q1.
Line no. Operating line
2250 Pump overrun time
Pump overrun time after Heating mode and external requests for heat.
Line no. Operating line
2253 Pump overr time after DHW
Pump overrun time after DHW heating.
User Manual LMS14...
6 The settings in detail
CC1U7471en
07.05.2014