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Condensing boilers
modern condensing boilers can be over 90% efficient in their condensing mode. They manage to
achieve this much higher efficiency by making use of the from the normally wasted flue gas temperature, which is in
the region of 175 to 250°C. Extra pipe’s and heat exchanger is take this heat from the flu and use it to put back
into the water entering the boiler. Since the flue gases are now as low as 75°C the majority of water vapour in the
flu products becomes liquid giving up its latent heat, hence the term condensing. As a result of the condensing
action there is a weak acid solution of water which must be discharged from the boiler via a condensate pipe. The
condensate pipe is usually a small plastic 22 mm up hype which extends from the boiler to the nearest waste point,
quite often this is under the sink. Ideally the condensate pipe should have a continual fall from the point it
leaves the boiler up until the point that connects the waste pipe. If a constant for he is not possible then that a
condensate pump can be used. The fact that the boiler as a condensing action this also means that the flu must be
positioned in such a way that the resultant liquid can fall there down with the flu into the boiler and away
through the condensate pipe.
Boiler installation London
Most traditional boilers other single
combustion chamber enclosed by the waterways of the heat exchanger, through which the hot gases can pass and the
eventually expelled from the boiler into the flu at high temperatures. Condensing boilers on the other hand, are
designed to first allow the heat to rise upwards through a primary heat exchanger, then at the top of the heater
the flue gases are divided and turned 180° to passed back down over to secondary heat exchanges the two second
dairy heat exchanges reduce the flow gas temperature to about 55°C, this reduction of temperature calls as the
water vapour, formed during the combustion of the fuel, to be condensed out the last releasing the latent heat
which would otherwise escape with the move gases. As the flue gas temperature is reduced the droplets of water
formed for by gravity to collect at the base of the flue manifold. From here a condensate drying allows the liquid
to run off as described above. Remaining gases are expelled to the outside environment through a fan assisted
balanced flue. The main point of a condensing boiler is to make the system a lot more efficient. Older boilers can
be as low as 50% efficient where as modern condensing boilers which are SEDBUK A rated are over 90% efficient. This means that with old less efficient gas boilers, it
is possible that up to 50% of the gas is being wasted. All new boilers being fitted by boiler installers are
condensing boilers even if they are attached to older open vented central heating systems.
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