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34
AST 14 C 259/00
BOILER FREEZE PROTECTION FUNCTION
When flow water temperature reading drops below 5 °C, a freeze protection operation
request will be developed, followed by burner turning on. At the end of the ignition
sequence, the gas flow rate supplied to burner will be forced to heating min. value.
The operation request during the freeze protection phase continues until flow water
temperature reaches 30 °C or an operating time of 15' is reached.
Any other operation request has higher priority, thus forcing the interruption of the function
in progress.
During a boiler freeze protection function, pump is powered. If flame control is locked and
burner cannot be ignited, the freeze protection function carries anyway out a pump
circulation. The freeze protection function is enabled both during "summer" and "winter"
operating modes. When boiler is in the "stand-by" condition, only pump, and not burner,
will be ignited.
WARNING: this function protects the boiler only, and not the central heating.
PUMP POST-CIRCULATION FUNCTION.
At the end of a request during heating, freeze protection or flue cleaning functions, burner
will be immediately switched off, while pump will continue to be powered for a time equal
to the one set by P5 parameter (default setting: 30 seconds).
If the CENTRAL HEATING function is enabled, pump will be turned on also when flow
water temperature reaches a value of 80 °C. As soon as flow water temperature goes
below 78 °C, pump will execute a 30-second post-circulation, and then turns off.
At the end of a request during DHW function, a 6-second post-circulation function will be
carried out if boiler is working in WINTER mode, or a 1-second post-circulation if boiler is
working in SUMMER mode.
Any operation request during CH, DHW, freeze protection functions will have higher
priority, and thus the post-circulation function in progress will be forced to end in order to
carry out such a request.
Function Time
After a CH, freeze protection or flue cleaning request
P5 (0 to 180 sec)
default setting: 30
sec
After a DHW request
6 sec in winter
1 sec in summer
For heating temperature > 80°C
30 sec
DESCRIPTION ON
OFF
Flow freeze protection function
5°C
30°C
(or after 15' of operation)