Thermostatic Radiator Valves

Thermostatic Radiator Valves (TRV’s) are used to automatically control the flow of hot water into a radiator according to the temperature in the room. They are used by many plumbers in conjunction with programmers and digital room thermostats to update heating systems to energy efficient standards. You can buy TRV’s from Screwfix in white and chrome.

Before we begin please watch this instructional video on how thermostatic radiator valves work:

How do TRV’s Work?

TRV thermostatic radiator valve

TRV’s have a basic operation. They measure the temperature in the room with a highly responsive metal spring filled with wax or liquid. When the room gets hot, the liquid in the spring expands and pushes on the valve jumper. This slowly closes the valve.

Where can I install a TRV?

Install TRV’s on radiators throughout the house. Leave one radiator (usually the towel radiator in the bathroom) with no TRV on it, just lockshields. Do not fit a TRV on the radiator in the same room as your room thermostat. As the radiator valve closes and cools the air, the room thermostat will never reach it’s set temperature and shut the boiler off.

Why install TRV’s?

They save you money in heating bills because you use less fuel when the radiators are closed. They also keep your house at a more ambient and controlled temperature.

Problems with TRV’s

My Radiator won’t get hot.

All TRV’s have a small pin that is the valve jumper. These can get stuck especially after a summer of being closed. Remove the TRV knob. They come apart either by unscrewing a holding ring or removing a plastic lug and twisting the collar. Once the head is off you should see a pin. Lightly tap this pin with a small hammer or move in and out with a set of pliers. When you feel the radiator get hot you’ve fixed the problem.