This European Standard specifies the requirements and test methods for the construction, safety, fitness for purpose, rational use of energy and the marking of a micro combined heat and power appliance; (hereafter referred to as “mCHP appliance”). This European Standard applies to mCHP appliances of types B22, B23, B32, B33, B52, B53, C1, C3, C4, C5, C6, and C8 as classified in CEN/TR 1749– that use one or more combustible gases of the three gas families at the pressures stated in EN 437,– where the temperature of the heat transfer fluid does not exceed 105 ºC during normal operation,– where the maximum operating pressure in the – heating water circuit does not exceed 6 bar,– domestic hot water circuit (if installed) is max. 10 bar,– which can give rise to condensation under certain circumstances,– which are declared by the manufacturer to be “condensing appliance”,– which are intended to be installed in a partially protected place,– which are intended to produce hot water either by the instantaneous or storage principle,– which have a maximum heat input (based on net calorific value) not exceeding 70 kW,– which are designed for sealed or open water systems.NOTE 1 For applications where the maximum allowable temperature exceeds 110 ºC or where volume multiplied by maximum allowable pressure exceeds 50 bar.litres, further requirements may be necessary to comply with the essential requirements of Directive 97/23/EC (Pressure Equipment Directive (PED)). NOTE 2 For mCHP appliances with constructions that might not be fully covered by this European Standard or by another specific standard, the risk associated with the alternative construction shall be assessed.This European Standard applies to type testing only. This European Standard does not contain the requirements necessary for appliance capable of producing electrical energy without using the thermal energy.