How to Fix a Radiator Valve

What You'll Need
Adjustable Wrench
Paper Towel
Old Rags
Teflon Tape
Replacement Valve

To prevent damage to your floor and carpets, it's essential to fix a problem radiator valve as quickly as possible. Finding the source of a leak and dealing with the problem is a job that you will be able to carry out yourself by following these simple steps.

Step 1 – Find Source of Leak

When water is leaking from a valve, it's easy to mistake the source because it will run from one area to the next. Use a rag to dry the radiator valve completely, then press a paper towel against the various parts to see where the leak originates.

Step 2 – Tighten Gland Nut

If the water leaks from the valve spindle, use a wrench to tighten the gland nut slightly. Tighten the nut gently rather than forcing it as sometimes, a very slight adjustment will make the difference. If the leak persists, unscrew the gland nut and remove it before wrapping teflon tape around the spindle. Tighten the gland nut back into place.

Step 3 – Tighten Cap Nut

If the source of water is the cap nut, a very slight adjustment may solve the problem. Use the wrench to gently tighten the nut then dry the valve and check using a dry paper towel to see if the leak has stopped. If this is unsuccessful, you can try replacing the olive within the valve rather than replacing the whole valve as a single component. Drain the radiator and unscrew the cap nut before removing the fitting. Replace the olive with a new one. Before you insert the new olive, either wrap some teflon tape around it or cover it in silicone sealant. Replace the fitting and cap nut and check for any leaks.

Step 4 – Remove Valve

If you still have water leaking from the valve, you will need to replace it. Depending on your heating set-up, you may need to drain the entire system. However, most times you will only need to drain the specific radiator which the valve is attached to. If you are in any doubt, check with a professional before beginning.

Before removing the existing valve, check that your replacement is exactly the same. Small differences in the valve can make them incompatible and impossible to align correctly. Hold the body of the valve with a wrench then use another to unscrew the cap nuts attaching the valve to the water pipe and the radiator. Lift the valve out of position.

Step 5 – Replace Valve

Unscrew the valve adaptor from the radiator and wipe the threads down with a damp cloth or old rag. Wrap teflon tape round the threads of the new valve adaptor before screwing it into place. Position the valve cap nut and olive and screw in the cap nuts to attach it to the radiator. Use the same method of support with a wrench on the valve body to allow you to tighten the cap nuts on the valve and water pipe. Refill the system with water and bleed the radiators to get rid of any remaining air. Check your new valve for leaks and tighten the cap nuts a little more if required.