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.
Low-pressure boilers are limited to a maximum working pressure of 15 psig (pound-force per square inch gauge) for steam and 160 psig for hot water (2). Most boilers used in HVAC applications are low-pressure boilers.hese types of boilers can be used to produce low or high pressure steam or water, and may be good alternatives for customers who are restricted by emissions regulations. Sizes range from 30,000 to 11,000,000 BTU input with overall efficiency generally in the range of 92% to 96% (2).