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Siemens Building Technologies Basic Documentation RVA53.242, RVA53.242 CE1P2373E
Landis & Staefa Division General control processes 26.03.2001
6.14 Frost protection
Ensures that the boiler and the d.h.w. temperature will not fall below a certain level
.
In addition to the frost protection modes described here, frost protection for the building
and frost protection for the plant, whose parameters can be set, are also active. For
details, refer to the description of lines 28 and 34
OEM
.
6.14.1 For the boiler
If... then...
the actual boiler temperature falls below 5 °C...
(TKx < 5 °C)
... the frost protection
function for the boiler
becomes active
The actual value of the boiler temperature exceeds the
minimum limitation of the boiler temperature (line 81) by
more than one boiler switching differential (line 3 OEM)...,
(TKx > TKmin + SDK)
... the frost protection
function will be terminated
If the frost protection function for the boiler is activated, the burner will be switched on
and the boiler water heated up until the frost protection function is terminated.
The frost protection setpoint for the boiler is factory-set at 5 °C and cannot be changed
Protective boiler startup remains activated within its functionality
The minimum burner running time (line 4 OEM) is taken into consideration
6.14.2 For the d.h.w.
If... then...
the actual value of the d.h.w. temperature falls below 5
°C...
(TBWx < 5 °C)
... the frost protection
function for the d.h.w.
becomes active
the actual value of the d.h.w. temperature exceeds 5 °C
by more than one d.h.w. switching differential (line 51
OEM)...
(TBWx > 5 °C + SDBW)
... the frost protection
function for d.h.w. will be
terminated
If the frost protection function for d.h.w. is activated, first the boiler water is heated until
the minimum limitation of the boiler temperature is reached (TKmin, setting on line 81),
then, the d.h.w. is heated by means of the charging pump or the diverting valve.
• The frost protection setpoint for the d.h.w. is factory-set at 5 °C and cannot be
changed
• Protective boiler start-up remains activated within its functionality
• The minimum burner running time (line 4 OEM) is taken into consideration
• Pump overrun will be activated when d.h.w. heating is terminated
• This function is not available when heating the d.h.w. with a control thermostat
Benefit
Description
Process
Effect
Note
Process
Effect
Note
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