Thermostatic Radiator Valve

A Thermostatic Radiator Valve, (TRV), is a self regulating valve fitted to hot water heating system radiators. The TRV controls the temperature of a room by regulating the flow of hot water to the radiator. TRVs consist of two parts, a valve that opens or closes to control the hot water flow, and an actuator that controls the opening of the valve. The actuator adjusts the valve opening based on the temperature in the room via a mechanical linkage or pin connected to the valve. The actuator is usually a plastic unit containing a wax plug, the wax plug expands or contracts as the temperature of the room rises or falls. The plastic unit is preset by a screw mechanism that positions the wax plug a set distance from the connecting pin. As the temperature of the room increases the wax expands, pushing the pin down and restricting the flow of hot water. As the room cools the plug contracts, the pin is let out a little and more heat is admitted into the room.  more