How Thermostatic Radiator Valves Work

Thermostatic radiator valves are the valves on the stems of hot water radiators that are not electric. These valves regulate the heat levels in a room by releasing or preventing steam or water to come from the boiler to the radiator. This piece is made using a valve that is connected to an actuator. The actuator, made of a wax plug, is inside an adjustable case and is a given distance from a metal rod or pin. The pin or rod is attached by the linkage to the valve. This linkage is spring driven.

How Does It Work?

When the temperature in a room increases, the wax plug on the actuator will expand. This causes the plug to push up against the pin or rod, which leads the valve to close, stopping more steam from going into the radiator. When the temperature in the room cools down, the wax plug contracts so it is no longer pressing against the pin or rod, thus telling the boiler to once again allow the steam to pass.

To adjust the temperature in a room using a thermostatic radiator valve, simply turn the plastic housing that surrounds the wax plug to either allow or restrict the flow of steam into the room.