Siemens LMS14 User Manual page 401

In all other cases, the status output is deactivated.
The status output is also used if power supply for an additional gas valve (e.g. for
liquefied gas in an external tank) is required.
With these types of application, output K35 remains activated if an open gas pressure
switch causes start prevention, and the burner control quits start prevention again when
gas pressure returns (gas pressure switch closes) and a heat request is pending.
If the gas pressure switch switches off during operation, output K35 is only deactivated
during postpurging. If the request for heat continues to exist and the burner control
goes to start prevention, output K35 is activated again to remain activated.
Status information K36
The output is switched when Operation phase (modulation) is active and when Status
output is selected for one of the relay outputs QX1...3.
Flue gas damper K37
Control of flue gas damper (refer to chapter Control of flue gas damper).
Fan shutdown K38
Function Fan shutdown to turn off power when the fan is not needed.
dT controller 1 K21 ¦ dT controller 2 K22
Relays K21 and K22 are used for the delta-T controller function.
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Building Technologies Division User Manual LMS14... CC1U7471en
6 The settings in detail 28.01.2015