Siemens LMS14 User Manual page 547

Shutdown
Home run
Building Technologies Division
The change from the operating position to Standby is made when there is no more
request for heat and is subdivided into Shutdown and Home run. Shutdown consists of
postpurging, which can be switched off. With postpurging, there are 2 possible modes
of operation, the difference being the way the fan is controlled.
Parameter setting choice 1:

THL2 (0.2 seconds)
Change to postpurging with fan control used last in operation.

TN1 (t8)
Postpurging with fan control used last in operation.

TN2
Interruptable postpurging with fan control used last in operation. If there is a new
request for heat during this postpurge time, postpurging can immediately be interrupted.
Parameter setting choice 2:

THL2
Change to postpurging with fan control used during prepurging.

THL2A
Postpurging with fan control used during prepurging.

TN2
Interruptable postpurging with fan control used last in operation. If there is a new
request for heat during this postpurge time, postpurging can immediately be interrupted.
The home run serves for making the change to the Standby position. It is made on a
regular basis after shutdown. After extraordinary events (refer to Sequence diagram) or
after a reset, it is used to bring the unit into the basic position (Standby). In the case of
a new request for heat, fast startup is triggered during the home run. This is
accomplished by reducing TNN followed by a direct change from phase TNN to phase
THL1/THL1A. In that case, operating state Standby is skipped.

TNB
Permitted afterburn time.

TLO
Permitted time with air pressure switch closed (if present) or fan speed > 9525 -
N_TL_Delta.

TNN
Permitted time with fan speed > NoG_Null.
User Manual LMS14...
6 The settings in detail
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28.01.2015