A bleed valve

A bleed valve (1) for releasably engaging a threaded bore (2) of an existing bleed 5 valve (3) of a burner (4) of a boiler/burner unit for bleeding an oil duct (5) of the burner (4). The bleed valve (1) comprises a housing (6) terminating in a threaded spigot (7) for engaging the threaded bore (2) of the bleed valve (3) of the burner (4). A threaded bore (14) extending into the housing (6) terminates in a valve seat (10) from which a communicating bore (11) extends through the spigot (7). An externally threaded carrier plug (15) engageable in the threaded bore (14) terminates at one end in a valving member (16) and at the other end in a spindle (17) which extends to a hand grip knob (19) externally of the housing (6)for rotating the carrier plug (15), Rotation of the carrier plug 15 urges the valving member (16) between an isolating state abutting the valve seat (10) for closing the communicating bore (11)1 and a bleed state with the valving member (16) spaced apart from the valve seat (10) for accommodating air bled from the oil duct (5) through the communicating bore (11) and in turn through an outlet port (20). Should the threads in the threaded bore (14) or the carrier plug (15) wear, the bleed valve (1) can be readily replaced with a replacement bleed valve (1).