Describes thermal efficiency requirements and associated methods of test for gas-fired central heating boilers with rated heat input up to 60 kW or 90 kW provided that they are part of a range of which at least 50 % have ratings below 60 kW, and gas-fired circulators of rated heat input not exceeding 8 KkW. It applies to the central heating boiler function of appliances that are designed also to supply instantaneous hot water. Includes sections on definitions, thermal performance, general requirements, efficiency requirements: still air conditions, efficiency requirements for natural draught type B appliances: adverse flue conditions, test methods, general conditions of test, measurement of efficiency and derivation of the formulae for calculation of the return water temperature to be used in the

BS 6332-1(1983) : AMD 4969

BS EN 483 : 2000