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.
The gas is pumped into the house to the burner for the boiler. The burner is lit by a pilot light that generally remains lit. To keep the boiler from overproducing, a temperature gauge and a thermocouple junction are used to regulate the flow of gas from the line to the boiler. The burner heats the boiler, which is a metal tank that generally holds water. A boiler that is used to heat water may also be referred to as a hot water tank.