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45
AST 14 C 258/00
AMBIANT THERMOSTAT
With the boiler set on the "DHW + CH" or "Hearing only" operating mode, the closing up of
ambient thermostat electric contact (as well as by the remote control or the zone board)
will result in a request making heating modulation start.
WARNING: with parameter P16 it is possible to delay the ambient thermostat
reading to allow the zone valves to open before the boiler pump starts (from 0 to 199
seconds).
AMBIENT THERMOSTAT TIMER (ANTIFAST)
During heating modulation, once the min. power supplied to the burner is reached and with
the supplied power above the required one, the burner is switched off.
After 240 sec from the burner switching off (P11 parameter) if the flow is lower than the
“set-point” the burner is switched on again.
The heating thermostat timer is reset:
upon a DHW request;
at the end of a heating request;
selecting the “standby” or “DHW” mode or resetting the boiler;
if the flow temperature value falls below the P27 parameter (40°C with standard range,
or 20°C with reduced range).
ADJUSTABLE HEATING MAXIMUM OUTPUT
During the operation in heating mode the maximum output provided to the burner is equal
to the one set by means of parameter P7 that corresponds to a percentage of the boiler
maximum power set through parameter P4.
TEMPERATURE RANGE PRE-SELECTION
With parameter P10, without any external probe, it is possible to set two ranges (standard
and reduced) to adjust the flow water by means of the boiler keys or the remote control:
P10 < 1
heating temperature reduced range: 20 ÷ 45°C
P10
≥
1
heating temperature standard range: 20 ÷ 78°C
Using an external probe instead, such parameter corresponds to the thermoregulation
curve selection (refer to paragraph “Thermoregulation with external probe”).
HEATING MODULATION WITH POWER ASCENT RAMP
Following a heating request by the ambient thermostat or remote control, if the water
temperature read by the flow NTC probe is lower than the heating thermostat intervention
ON temperature, consent is given to disable automatic flame control in order to start the
burner ignition sequence (ignition power - P6).
At the end of this sequence, the power provided to the burner reaches the negative ramp
power value (P8). It then passes from this value to the one set for the heating maximum
power parameter (P7), with a ramp duration equal to settable parameter P12.
