How To Fix A Leaking Radiator
If you've spotted dripping water from your radiator it could be a leaky radiator valve. While this can be a real pain, the good news is that it's often a simple fix.
You'll want to get it sorted as soon as you can, as a leaking radiator valve can result in water damage to your floors and decreased water pressure in your heating system, which may impact your boiler.
To prevent water damage and keep your heating in good working order, follow our step-by-step process on how to fix a leaking radiator.
Essential Tools & Equipment
Step 1: Turn Off the Radiator Valves to Isolate the Leak
Before you begin, shut off the radiator by turning the valves on both ends clockwise (righty tighty). This isolates the radiator from the heating system, and stops any more water from flowing into the radiators while you repair the valve.
Step 2: Release Pressure from the Radiator
Once the valves are shut, use a radiator bleed key to release any remaining pressure and water. Place a bowl directly beneath the valve to capture any water then loosen the bleed valve slightly until water or air stops coming out. Make sure to close the valve afterwards.
Step 3: Find Where the Radiator Valve is Leaking
Next up, you'll need to establish where the leak is coming from as radiator valves, sometimes called lockshield valves, can spring leaks from several different places. These can include:
- The threaded part which feeds straight into the radiator.
- At the Nut and Olive which sits on the pipe connecting it to the valve. There are two of these connections so be sure to check both of them.
- At the gland nut which connects to the radiator spindle. This is usually covered with a plastic cap to keep it hidden from view.
Carefully inspect each part to identify where the water is escaping from.
Step 4: How to Fix a Leak at the Radiator Insert
If the leak is coming from the thread that connects the valve to the radiator, use an adjustable spanner to loosen the horizontal nut and olive connection.
- Slacken it enough so that you can see the beginnings of the threaded part, around 4 or 5 threads should suffice.
- Clean the threaded part by removing any of the old sealant.
- Carefully apply new PTFE tape by wrapping it tightly around the threaded part. Make sure to wrap in an anti-clockwise direction as this will ensure the tape stays in place when you tighten the nut back up.
- Grab your adjustable spanner and tighten everything back up.
Step 5: How to Stop Leaks at the Nut and Olive
If the leak is coming from the horizontal nut and olive connection (where the valve meets the pipe), loosen off the nut and apply PTFE tape or a general-purpose sealant around the olive. As before, wind the tape in an anti-clockwise direction so it doesn't unravel when you tighten the nut back up. Tighten the nut carefully to avoid damaging the connection.
For a leak coming from the vertical nut and olive, you'll have to work fast to prevent excess water loss. Loosen the connection in the same way as with the horizontal nut and olive. Water will leak from the connection so ensure you've put something under the valve to capture it and be ready with your PTFE tape. Quickly wind the tape around the olive then tighten the compression nut back up.
Step 6: How to Seal a Radiator Valve Gland Leak
If the water leak is coming from the gland nut, start off by removing the plastic cap that covers it. Take your adjustable spanner and tighten up the nut, don't overtighten as this could make it harder to turn the valve on and off.
If the leak persists, unscrew the gland nut and remove it from the valve. Wrap PTFE tape around the gland, around 4 or 5 times should do. Pop the nut back on and tighten it back up. This should stop any leakage from the valve head.
Step 7: Turn the Water Back On and Test for Leaks
Once the repair is done, slowly reopen the radiator valves and let the water flow back into the radiator. Check all the connections for leaks. If everything is dry, you’ve successfully fixed your radiator valve!
