The gas fired radiant heater has a radiant tube (1) forming the combustion chamber. A burner (2) is fitted to one end of the radiant tube and burnt gas discharge occurs at the other end. The burner has a pre-mixing chamber coaxial with the radiant tube. An electrode fitted at the exit, lights the gas issuing from a nozzle coaxial with the pre-mixing chamber. The burner is fitted to the radiant tubes via a sleeve which slides axially along the tube and can be locked in any position.
