Plumbing Tips for Understanding and Installing Thermostatic Radiator Valves

Thermostatic Radiator Valves are more commonly known as TRVs. TRVs individually control the temperature of each radiator, so you can control the temperature in each room by understanding how these work.

So, how do TRVs work and what is the difference between a thermostatic radiator valve and a reuglar valve?

A regular valve (and the odds are that you have one of these if you don’t have a TRV) shuts on and off hot water flow by being turned (like a bath and bath tap).

Thermostatic Radiator Values automatically control the amount of hot water going into the radiator in accordance with the temperature of the room the radiator is already situated within. Pretty clever stuff! TRVs are chameleons of the heating world, changing to suit their environment.

There are two types of TRV you can get, the most popular controlled by a spring, which is susceptable to the temperature around it.

If the room is cold, the metal will contract. Therefore, the valve jumper will open, and hot water will be allowed to flow into the radiator. Equally, if the room is warm, the spring will do the opposite and expand, the valve will be pushed down, and the flow to the radiator will stop.

Can you install TRVs anywhere?

Unfortunately not.

Don’t put a TVR in the same room as the house thermostat. The radiator in the same room as the house thermostat needs to have a lock shied on it that is fully open, so that the house thermostat can always have an accurate reading.

So how do I install one?

Easy!

Make sure the water supply is turned off to the heating system. Allow air into all of the radiators that you want to change over to a TRV. When you use the Stop Cock Key to let out the air, you should hear the air escaping from the radiator.

Remove the old lock shield valve. Knowing that the system is drained, use a wrench to loosen the bolt. Then loosen off the 15mm pressure fitting at the bottom in the same way. Remove the fitting. Both the valve gonig into the radiator and also the valve coming up through the floor should now both be exposed and ready to fit the TRV in the place of your old lock shield valve.

All new TRVs are supplied with a new insert, so the old one that will be attached to the valve going into the radiator itself will need to be removed.

There are special tools called Radiator Spanners that can be used to aid you with this. The type you get will depend on the type of valve you have on your old shield valve.

Inserting the tool into the insert, you will normally need to use a wrench to turn the tool within the insert to loosen it. Continue by removing the old insert.

Now PTFE tape the new insert. Wrap the PTFE tape around the insert 10-12 times and insert into the radiator valve and tighten up using the wrench.

Add some PTFE tape around the valve fitted to the floor too and you are then ready to insert your nrew valve.

Put the new fitting back on and tighten up the bottom fitting first, before proceeding to tighten up the radiator valve fitting. Again, use the wrench to secure these tightly.

Remove the top cap of the new TRV and that will reveal to you the actual valve jumper, which moves up and down.

Now place the TRV fitting on top and you are ready for this chameleon radiator to warm up (or cool down) your room!

What tools do I need to make this happen?

• TRV replacement
• Wrench
• Stop Cock Key (to bleed the radiators)
• Radiator Spanner
• PFTE Tape