Abstract: Two stop valves, associated with bypass ducts containing energy absorbing devices, enable an adjustable fraction of the hot fluid to be diverted past left and right hand heating radiators, so that any change in the adjustment of the fluid flow in either of the radiators has no effect on the fluid flow in the other radiator.

Abstract: A heating and/or air conditioning installation for a motor vehicle includes a wall having a through hole. A temperature sensor has a heat sensitive element lying in a housing, which may for example be formed in an evaporator of the air conditioning installation. The sensor has protruding connecting wires surrounded by a sheath, and is attached through the hole in the wall by a fastening device. The fastening device comprises a tubular body portion adapted to be removably held fast in the hole, together with a sleeve portion joined to the inside of the body portion and having a passage through which the sheath passes. The sleeve portion has a narrow end which grips the sheath, and a wide end facing towards the heat sensitive element and affording some freedom of lateral movement to the connecting wires.