Be sure when purchasing new new burners that they are certified for K-gas. The burners from Saunatechnics have all been adapted and certified for k-gas. Due to the change in calorific values, the gas appliances must be adjusted. Otherwise they do not work well. Incidentally, there is only a transition to the mentioned K-Gas around 2033. From January 1, 2018 no gas appliances may be sold that can not handle the ‘new’ K-Gas.