The CE mark, or formerly EC mark, is a mandatory conformity marking for certain products sold within the European Economic Area (EEA) since 1985. The CE marking is also found on products sold outside the EEA that are manufactured in, or designed to be sold in, the EEA.
Condensing boilers are water heaters fueled by gas or oil. They achieve high efficiency (typically greater than 90% on the higher heating value) by condensing water vapour in the exhaust gases and so recovering its latent heat of vaporisation, which would otherwise have been wasted.
How Combi Boilers Work. Unlike conventional systems, combi boilers do not store domestic hot water. They heat water from the cold mains directly even as you use them. With combi boilers, you do not have a hot water cylinder, loft tank, or pipework.Combis are like standard unvented boilers but they have a second heating circuit, which is what gives you the instant hot water whenever you need it.f fed directly from the main water supply to the heat exchanger, the combi boiler can have an unlimited hot water supply as long as the boiler is firing. Combis manage to extract a larger amount of heat from the flue gases that escape from the flue system, which increases the combi's efficiency.