Heating boilers - Part 1: Heating boilers with forced draught burners - Terminology, general requirements, testing and marking; German version EN 303-1:2017
Edition 2017-11

Heating boilers - Part 2: Heating boilers with forced draught burners - Special requirements for boilers with atomizing oil burners; German and English version prEN 303-2:2023
Edition 2023-04

Heating boilers - Part 2: Heating boilers with forced draught burners - Special requirements for boilers with atomizing oil burners; German version EN 303-2:2017
Edition 2017-11

Heating boilers - Part 3: Gas-fired central heating boilers - Assembly comprising a boiler body and a forced draught burner; German version EN 303-3:1998 + A2:2004
Edition 2004-10

Heating boilers - Part 3: Gas-fired central heating boilers - Assembly comprising a boiler body and a forced draught burner; German version EN 303-3:1998 + A2:2004, Corrigenda to DIN EN 303-3:2004-10; German version EN 303-3:1998/AC:2006
Edition 2007-07

Heating boilers - Part 4: Heating boilers with forced draught burners; special requirements for boilers with forced draught oil burners with outputs up to 70 kW and a maximum operating pressure of 3 bar; terminology, special requirements, testing and marking; German version EN 303-4:1999
Edition 1999-03

Heating boilers - Part 5: Heating boilers for solid fuels, manually and automatically stoked, nominal heat output of up to 500 kW - Terminology, requirements, testing and marking; German version EN 303-5:2021+A1:2022
Edition 2023-07

Heating boilers - Part 6: Heating boilers with forced draught burners - Specific requirements for the domestic hot water operation and energy performance of water heaters and combination boilers with atomizing oil burners of nominal heat input not exceeding 70 kW; German version EN 303-6:2019
Edition 2019-12

Heating boilers - Part 6: Heating boilers with forced draught burners - Specific requirements for the domestic hot water operation and energy performance of water heaters and combination boilers with atomizing oil burners of nominal heat input not exceeding 70 kW; German and English version EN 303-6:2019/prA1:2022
Edition 2023-01

Heating boilers - Part 7: Gas-fired central heating boilers equipped with a forced draught burner of nominal heat output not exceeding 1 000 kW; German version EN 303-7:2006
Edition 2007-05