GOST R 53634-2009 Gas-fired central heating boilers, type B boilers, of nominal heat input exceeding 70 kW, but not exceeding 300 kW. General technical requierements and test methods
1970GOST R 53634-2009 Gas-fired central heating boilers, type B boilers, of nominal heat input exceeding 70 kW, but not exceeding 300 kW. General technical requierements and test methods