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77
AST 14 C 255/00
External probe fault
(E23)
: each operation request in heating mode entailing the
burner ignition is carried out ignoring the calculation algorithm: the curve value is
used to determine the operation range (standard or reduced) with set-point
corresponding to the set one.
Correct operating range:
from -40 to +50°C, general tolerance: +/- 3°C
.
Ambient probe
(E44, E45)
fault: each operation request in heating mode entailing
the burner ignition is carried out ignoring the calculation algorithm. Flow set-point is
the one available in the configuration with P57=4.
Correct operating range:
from -40 to +50°C, general tolerance: +/- 3°C
.
Warning: if the boiler or the remote control is in "OFF" mode, the fault is only signalled,
whereas all the other boiler control elements (gas valve, fan, pumps, three-way valve,
multifunction relay) remain in the rest position.
ANTI-SHUT-DOWN FUNCTION
Boiler pump, deviating valve, and DHW pump
The electronic board calculates the time elapsed since boiler pump disabling; if this time is
equal to 24 hours, the pump along with the deviating valve (P28=0) or the DHW pump
(P28=1) will be enabled again for 30 seconds.
During the pump anti-seizing function the burner remains off and upon each activation of
the pump for any request the timer is reset.
Any operation request in CH, DHW or anti-freeze mode will have higher priority, and thus
the function in progress will be forced to end in order to carry out such request.
Multifunction relay
The multifunction relay carries out the anti-shut-down operation as indicated in the
previous paragraph only if it is set as pump or valve (P17=1, P17=2 and P17=3).
In case it is set to signal faults and errors (P17=0) the relay does not carry out the anti-
shut-down operation.
POST-VENTILATION FUNCTION.
Upon burner switching off, the fan is still supplied with power for 10 seconds (super-
technical parameter P94), regardless of boiler operating mode.
Moreover, a post-ventilation cycle is started when the temperature read by the flow probe
reaches 95°C and is stopped when the temperature falls below 90°C.
Any operation request during CH, DHW, anti-freeze, flue cleaning functions will have
higher priority and thus the ventilation function in progress will be forced to end in order to
carry out such request.
