4.4.2.
Combustion
The burner heats the heating water circulating in the heat
exchanger. At a return temperature lower than around 55°C, the flue
gases cool down to a temperature lower than the dew point, thus
causing the condensation of the water vapour contained in the flue
gases in the lower section of the heat exchanger. The heat released
during this condensation process (the latent heat or condensing heat)
is also transferred to the heating water. The cooled combustion gases
are evacuated via the combustion gas outlet flue. The condensation
water is evacuated via a condensate trap.
4.4.3.
Heating and domestic hot water production
On combi boilers, an integrated plate exchanger heats the domestic
water. A 3-way valve determines whether the heated water is fed into
the heating system or the plate exchanger. A pick-up sensor signals
that a hot water tap is being opened. This signal is transmitted to the
control panel, which then switches the 3-way valve to the hot water
position and trips the heating pump. The 3-way valve is spring-loaded
but only consumes electricity when it switches to another position.
The heating water reheats the domestic water in the plate
exchanger. In comfort mode, if there is no hot water draw-off, the
boiler handles the periodic reheating of the plate exchanger. Any
limescale particles are kept out of the plate exchanger by a self-
cleaning water filter (self-cleans once every 76 hours).
4.4.4.
Control system
Control of the boiler ensures reliable delivery of heat. This means that
the boiler treats external negative influences in a practical manner
(notably when the water-flow is insufficient or there are problems with
air supply). In the presence of such influences, the boiler doesn’t
switch into locking mode, but first reduces his power and, depending
on the nature of the circumstances, will be temporarily out of service
(blocking or stop). The boiler will continue to supply heat as long as
the situation does not become dangerous.
4.4.5.
Adjustment
The power of the boiler can be adjusted in the following ways:
4
On/Off setting
The output between the minimum and maximum values varies
based on the heating flow set point temperature.
4
Adjustable control
The output between the minimum and maximum values varies
based on the heating flow temperature determined by the
modulating control system.
Baxi MainEco Combi and System 24 - 28 - 35 / 18 - 24
4. Technical description
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