This standard specifies the additional requirements and test methods for gas-fired air heaters which are so designed that water vapour condenses from combustion products. On this subject it extends the European standards EN 778 and EN 1319 for domestic, and EN 621 and EN 1020 for non-domestic air heaters. This standard applies to gas-fired air heaters with or without a fan in the combustion circuit in one of the following constructional types: ð an integral air heater with at least one condensing heat exchanger ð a non-condensing air heater with an integrated additional condensing heat exchanger ð a non-condensing air heater, with an integrated additional condensing heat exchanger for the recovery of heat from combustion products and from ventilation air if appropriate. This European Standard covers type-testing only.