Unit 309 session 4b Gas boilers

​Gas central heating boilers

​Gas central heating boilers are the most popular of all central heating appliances. Over the years there have been many different types

​Central heating boilers can be categorised as:
● traditional boilers (non-condensing)
● traditional (condensing)
● cast iron heat exchanger
● low water content heat exchanger
● combination boilers
● condensing boilers (system and combination boilers).

​Traditional boilers use one heat exchanger to heat up the primary water and are less efficient, allowing the latent heat to be expelled to atmosphere.