The experimental research of intensity of a thermal stream and distribution of temperatures on ribbed pure and low-purity surface of the tubular ridge convector with spiral aluminium ribs is spent at air free convection. Researches were spent by a method of full thermal model testing at specially developed experimental stand, and ring uniform pollution ribbed tubes was created by dense winding between ribs of a linen cord or wrapping of tube by an aluminium foil. It is revealed that at a free convection in tubes with a close arrangement of ribs of pollution of intercostal space at the basis оребрения does not lead to essential decrease in a heat rating (less than 10 %), and the decline to give heat properties of a tube occurs only at pollution of cops ribbed (on 20,5 %). The temperature on altitude of a lateral surface of a rib decreases slightly (less than 2 %), and on a rib cop in relation to the basis - for 6-9 %. Hence, at maintenance of ridge convectors of systems of heating their frequent and careful clearing of pollution is not obligatory.