DE DIETRICH TWINEO EGC 25 - Manual (Page 10)

3 Description
3.1 Operating principle
3.1.1. Gas/air setting
Air is sucked in by the fan and the gas injected into the venturi
attached to the fan inlet. The fan rotation speed modulates and adapts
to thermal energy requirements thanks to the temperatures measured
by the various sensors. The gas and air are mixed in the venturi, which
enables operation at a constant ratio. The noise of the venturi is
absorbed by a silencer attached to its inlet. The gas/air mixture is
carried to the burner in the top of the exchanger, guided by the pre-
mix channel.
3.1.2. 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 siphon.
3. Description EGC 25
9 03/12/2013 - 300026082-001-02