ČSN EN 15502-2-1+A1
Kotle na plynná paliva pro ústřední vytápění - Část 2-1: Zvláštní norma pro kotle provedení C a kotle provedení B2, B3 a B5, se jmenovitým tepelným příkonem nejvýše 1 000 kW

ČSN EN 15502-2-1+A1

This European 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".
Where the word boiler is used, it needs to be read as the boiler including its connecting ducts, ducts and terminals, if any.
This European Standard covers gas-fired central heating boilers from the types C1 up to C9 and the types B2, B3 and B5: