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5. boiler protection devices
5.5 Anti-frost Device.
The anti-frost function acts on the central heating fl ow
temperature probe, independently from other operations,
when the electrical supply is turned on.
If the primary circuit temperature is between 3°C and 8°C the
pump will run (with the diverter valve switching between central
heating and hot water every 1 minute) until the temperature
reaches > 9°C.
If the fl ow temperature remains
between 3°C and 8°C the pump will
continue to run for a maximum of
20 minutes unless a temperature
above > 9°C is detected in the
central heating fl ow, after this the
the burner will fi re (heating position)
until a temperature of > 30°C is detected.
If
the
central
heating
fl ow
temperature is < 3°C, the burner will
fi re (heating position) at minimum
power
until
the
temperature
reaches > 30°C, the burner will go
out.
If lockout is caused by overheat the
burner will not fi re but the pump will continue to run (heating
position).
The anti-frost device activates only when (with the boiler
operating correctly):
- the system pressure is correct;
- the boiler is electrically powered;
- there is a supply of gas.
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