BS EN 656:2000

This standard BS EN 656:2000 Gas-fired central heating boilers. Type B boilers of nominal heat input exceeding 70 kW, but not exceeding 300 kW is classified in these ICS categories:

• 91.140.10 Central heating systems

This standard specifies the requirements and test methods concerning, in particular the construction, safety, fitness for purpose, and rational use of energy, as well as the classification and marking of gas-fired central heating boilers that are fitted with atmospheric burners, fan assisted atmospheric burners or fully premixed burners, and are hereafter referred to as “boilers”.

This standard applies to boilers of type B, as listed in 4.2:

• of the low-temperature type;

• that use one or more combustible gases of the three gas families at the pressures stated in Tables 14 and 15;

• that have a nominal heat input (net CV basis) exceeding 70 kW, but not exceeding 300 kW, including modular boilers;

• where the temperature of the heat transfer fluid does not exceed 105 °C during normal operation;

• where the maximum operating pressure in the water circuit does not exceed 6 bar.

• of the standard type possibly producing condensation in certain circumstances;

The standard applies to boilers designed for sealed water systems or for open water systems.

The standard does not contain all the requirements necessary for boilers:

• intended to be installed in the open or in living rooms;

• permanently fitted with more than one flue outlet;

• where the combustion circuit is sealed with respect to the room where the boiler is installed;

• of the condensing type;

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• intended to be connected to a common flue having mechanical extraction;

• fitted with a forced draught burner in accordance with EN 676;

• producing hot water for domestic purposes.

This standard only covers type testing.