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.
Every set of tubes that the flue gas travels through is considered a âpassâ. Boilers designed for three-passes have the stack at the rear, and boilers designed for four-passes have the stack at the front. A boiler with more passes has a higher heat extraction rate and is more efficient then one with less passes. Watertube boilers are safer by design and generally can operate many years longer than firetube boilers.