What should I do if my radiator is leaking?

If you find water at the base of your radiator DO NOT IGNORE IT. You can deal with a leak simply, safely and cheaply if you follow these guidelines:

  1. Get a bucket and some (old) towels. Without these, things could get messy!
  2. Find the source of the leak. Dry the entire radiator with a towel. Then using some tissue paper, systematically check every joint and valve to see where the leak is coming from.
  3. Leaking radiator valve? If the valve at the bottom of your radiator is leaking, the packing around its spindle may have become worn. Closing the valve fully should stop the leak.
  4. Valve repair. First, you need to drain the system down to below where your leak is. Turn off the supply valve (where the water enters the radiator) and the plastic-capped lockshield valve (remembering to count how many turns it takes). Use towels and a bowl to catch any excess water. Next, undo the union nut between the feeder pipe and radiator. Open the bleed valve which will allow the remaining water to run off into the bowl. Wrap the valve tail with PTFE tape 10-15 times. Retighten the union nut and open the bleed and lockshield valves - remember how many turns it took previously to close the lockshield valve. Once water has returned to the system, check again for leaks and close the bleed valve.

If your leak comes from a hole in the radiator itself, then you will need a new one. Isolating the radiator by closing the supply and lockshield valve will prevent leakage until it can be replaced.

Remember, plumbing faults can be damaging and expensive. If you’re not confident about making a repair yourself, leave it to the professionals.

Help & advice

Why is my radiator making a noise?

A noisy radiator is usually caused by air trapped inside the system. Inefficient radiators can waste both energy and money but this can be solved quickly and simply by bleeding your radiators.

How do I bleed my radiators?

Bleeding a radiator simply means getting the air out of it and it’s really straightforward. Here’s how you do it:

  1. Switch off your boiler - to avoid getting splashed by hot water.
  2. Get your bleed key. If you don’t already have one, you can get a bleed key from any hardware or DIY store for less than a fiver.
  3. Open the bleed valve. Use the key to turn the valve (at one of the top corners of your radiator) about a quarter turn anti-clockwise. It’s unlikely much water will come out of the valve but have a container and some towels ready just in case.
  4. Close the bleed valve. There will be a hissing sound as the air escapes from the valve. As the hissing stops and water begins to appear, close the valve by turning it firmly in a clockwise direction.

If you’re in any doubt, a professional plumber can perform this task for you, but in most cases, these simple guidelines should be all you need.

What should I do if my radiator is not working?

Sometimes a radiator isn’t noisy or leaky, it’s just cold. If that’s the case, ask yourself the following:

  1. Is the radiator only partly cold? If it’s only cold at the top, try bleeding the radiator to free the trapped air. If the bottom half of the radiator is cold, it has a layer of sludge in it. The radiator will need to be removed from the system and rinsed through. Don’t do this unless you’re fully confident how to proceed.
  2. Is the entire radiator cold? If so, check that the lockshield valve and supply valve (at the bottom of the radiator) are open. Remove the lockshield valve cap and check the pin is moving freely. If not, a tap should free it up. If things don’t improve after this, switch off all the other radiators to see if the faulty one won’t heat up. If it does, turn the other radiators on one by one and you can identify which one will need bleeding to solve the problem.
  3. Should I call a professional? If the radiator still won’t heat up, you might need to replace the valve. If you’re not fully confident of your ability to do this, call a plumber.

If you have any further questions regarding difficulty with radiators, or you need help finding a plumbing and heating professional, our team will be happy to help out.