A radiator valve leaking can cause all sorts of trouble in your house. It’s not just the mess the water can make. The pressure drop from the leaking radiator valve can cause your boiler to develop a fault cutting off your hot water and heating.
Where is my radiator valve leaking from?
Radiator valves have four places they can leak from.
The gland
The gland is the part of the radiator valve that seals the spindle that you turn to open or close the valve.
When this is worn out from a lot of use or is used for the first time in a long time it can leak.
The connection to the radiator tail
This connection is between the radiator valve and the radiator tail. Most modern radiators have a 15mm compression connection, and some older radiator valves may have a 3/4 inch connection.
The connection to the heating pipework
The valve will have a pipe coming into it, normally from underneath that is connected to your central heating system.
The radiator tail
The connection between the radiator valve and the radiator itself is called the tail. Most modern radiator tails are 1/2 inch threaded, wound into the radiator, and a 15mm compression joint connecting to the valve.
Some older valves and tails require a special radiator tail spanner to wind them in and out.
How do I fix the leaking radiator valve?
Fixing a leaking radiator valve is a mid-difficulty plumbing job. If you aren’t confident or don’t know much about plumbing please get a professional to help. You will need towels, a tray to catch any water, a waterproof dustsheet, and possibly a bucket.
You will also need appropriate-sized spanners and PTFE tape. Pump pliers can be used but they will wreck the surface of any valves and strip the chrome from fittings. If you aren’t bothered about aesthetics then pump pliers are great however for most jobs an adjustable spanner is much better.
Which type of system do you have?
The most important place to start is to ask what kind of heating system do you have? If your system has a pressure gauge it will be considerably easier to repair than if there are tanks in the loft.
The gland
A leaking radiator valve gland can normally be repaired by slightly tightening it with a small spanner.
If this doesn’t work the top nut can be removed and PTFE tape pushed in the gap around the spindle of the valve.
This creates a new gland that holds the central heating water in.
The connection to the radiator
Try to tighten the compression nut while holding the valve in position. Most times it will just need to be gently tightened.
If this doesn’t work you may have to remake the compression joint with some PTFE tape.
Turn off both radiator valves (either end of the radiator)