Heating apparatus, apparatus producing heat and hot water functioning on gas, electricity or solar energy, heat pumps, apparatus for producing hot water and heating simultaneously, heating and/or hot water boilers, air conditioning apparatus and systems, solar collectors, feeding apparatus for heating boilers, flues for heating boilers, boiler pipes for heating installations, boiler installations for hot water, electric heating filaments, heating installations, bath heaters, water heaters, burners, heat exchangers, dampers (heating), thermostatic valves (parts of heating installations), minimum power reduction ramps for boilers