Frost Protection For The Boiler - Siemens LMS14 User Manual

Setpoint frost protection
Additional parameters
Building Technologies Division

6.11.5 Frost protection for the boiler

Line no. Operating line
2217 Setpoint frost protection
The setpoint for the boiler's frost protection can be set by the OEM.
Frost protection for the boiler is ensured, independent of heat requests or connected
plant components. Therefore, boiler control checks frost protection autonomously and
also causes the burner to be started up, if necessary.
Frost protection for the boiler is activated whenever the boiler temperature drops below
the Frost Protection setpoint.
The switch-off threshold is determined
as follows:
The boiler temperature setpoint is
determined as follows:
If Ctrl boiler pump/DHW valve (5774) is set to All requests, the boiler pump runs during
the time frost protection for the boiler is active.
If set to Request HC1/DHW only, the boiler pump will not be activated.
If the boiler pump ran during the time frost protection for the boiler was active, pump
overrun is performed when frost protection for the boiler has ended.
If Setpoint frost protection (2217) is set to OSV (- - -), frost protection for the boiler is
not deactivated, but the frost protection setpoint is set to -20 °C.
Line no. Meaning
2454 SdHkEin
2455 SdHkAusMin
5774
User Manual LMS14...
6 The settings in detail
Switch-off threshold boiler =
Frost protection setpoint + Switching diff
on HCs (2454) + Switching diff off min
HCs (2455)
Boiler temperature setpoint = frost
protection threshold + Switching diff on
HCs (2454) + Switching diff off min HCs
(2455)
Switch-on differential heating circuits
Minimum switch-off differential heating circuits
Control boiler pump/DHW diverting valve
203/617
CC1U7471en
07.05.2014