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50
AST 14 C 257/00
HEATING CONTROL
With the boiler in DHW+HEATING or Only Heating mode, closing of the ambient
thermostat electrical contact (as well as consent from the remote control or the zone
board) generates a request, leading to Heating modulation.
IMPORTANT. With parameter P16, it is possible to delay the ambient thermostat
reading to allow the zone valves to open prior to activation of the boiler pump (from
0 to 199 seconds).
AMBIENT THERMOSTAT TIMER (ANTI-FAST)
During heating modulation, when the minimum power to the burner has been reached and
with it exceeds the required, the burner switches off.
Following burner switch-off, there is a time lapse of 240 seconds (parameter P11), after
which the burner re-ignites if the flow temperature is lower than set-point temperature..
The heating thermostat timer resets:
•
when there is a DHW request;
•
at the end of a heating request;
•
when the Stand-by or DHW modes are selected or by resetting the boiler;
•
if the flow temperature drops below parameter P27
(40°C w ith standard range, or 20°C w ith
reduced range).
ADJUSTABLE MAXIMUM HEATING OUTPUT
During operation in heating mode, maximum power provided to the burner is equal to the
one set for parameter P7, which corresponds to a percentage of the boiler maximum
power set for parameter P4.
TEMPERATURE RANGE PRE-SELECTION
With parameter P10, in the absence of an external probe, you can set two ranges
(standard and reduced) to adjust the flow water on the boiler keypad or the remote control:
P10 < 1
Æ
heating temperature reduced range: 20-45°C
P10
• 1
Æ
heating temperature standard range: 20-78°C
In the presence of an external probe, this parameter corresponds to the thermoregulation
curve selection (refer to the section entitled 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 (set 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.
The flow water temperature is read constantly and the ramp is interrupted when the flame
modulation point is reached with a PID-type action, until the set heating temperature is
reached and maintained.
