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68
AST 14 C 258/00
flame control shuts down and the burner cannot be ignited, the anti-freeze function
activates pump circulation.
Tank heater (KRB only)
The tank heater NTC probe measures the temperature of the water in the tank heater.
When this value falls below 5°C, a tank heater anti-freeze operation request is generated.
The pump activates and after a 30-second delay, the burner ignites with the output forced
to the minimum value.
During a tank heater anti-freeze operation the temperature read by the flow probe is kept
monitored and if it reaches 60°C the burner switches off. The burner switches on again if
the request for anti-freeze mode is still present and the flow temperature is lower than
60°C.
The request for operation tank heater anti-freeze mode ends when the tank heater
temperature exceeds 10°C or when an operating time of 15 min. is reached.
Any request for operation on heating or DHW mode has priority, and causes the function in
progress to terminate.
The anti-freeze function is active with the boiler regardless of the operating mode. If the
flame control shuts down (when it is impossible to ignite the burner), the anti-freeze
function performs a circulation of the pump with the three-way valve on DHW mode.
ANTI-LEGIONELLA FUNCTION
(KRB only)
The anti-legionella function is available on the boilers in the tank heater version (P3=3),
and it is always enabled. This function activates at the end of every 15-day period. After
this time, a tank heater heating phase starts up with the fixed set-point at 65°C. It lasts 30
minutes.
The anti-legionella function takes priority over any DHW, heating or anti-freeze cycle in
progress at the time when this function activates.
Warning: this function is executed only on DHW tank heaters managed with a
temperature probe.
DESCRIPTION ON
OFF
DHW anti-freeze function
5°C
10°C (or after 15’ of operation,
or if the flow temperature is
> 60°C)
General temperature tolerance
± 3°C
DESCRIPTION ON
OFF
Tank heater anti-freeze function
5°C
10°C (or after 15' of operation)
General temperature tolerance
± 3°C
