New Condensing boilers, the rudimentary truth

A condensing boiler is a efficient advanced boiler that integrates an additional heat exchanger to enable the hot exhaust gases transfer most of their heat to pre warm the mains water to be heated. When working at maximum efficiency, the water steam developed in the combustion process turns revert back into liquid form relinquishing the latent heat of vaporisation.

A consequence is that this water, refered to as condensate, most times acidic, will need to be piped outside to a drain or soakaway. The boiler will have to be mounted on a wall and the waste fumes will rise through the flue. Hot water is supplied by a small-scale recepticle tank to facilitate rapid hot water accessibility.

Can you suggest on the right boiler size?

You should keep in mind that when first fitted central heating engineers frequently put in boilers that had a higher output than purely necessary.. Whilst this meant that there was never the chance of the boiler failing to meet the demand for heat, even in the coldest winters, it also meant that they were only employing a piece of their heat generation capabilities, and so functioning below their maximum efficiency. If you have installed additional loft or cavity wall insulation since the last boiler was fitted, it could well be that you will need a humbler boiler than the current one.

Before you purchase a new boiler we advocate you get advice from a CORGI registered fitter.

Do I need to fit oversize radiators with condensing boilers??

The main driver for smaller fuel use from a condensing boiler results from having a bigger heat exchanger. Larger radiators would result in cooler return water temperatures, and so result in even better energy performance, but the additional economies suffer from diminishing returns, as you should consider the fact that that the system is is only using a small part of its total capacity for the main heating months. Whilst this affirmation is correct homeowners would probably accept this in smaller properties.

The SEDBUK initiative considered these subjects, and evaluated whether there required to be new considerations for condensing boilers. The conclusion was that they need not, and the test results for both cases use the same SEDBUK computation.