What To Do If Your Radiators Aren’t Heating Evenly

radiators aren’t heating evenly


It’s that time of year where the heating is suddenly on for longer periods, and usually the time of year when we discover something wrong with our heating systems. After a long period of non-usage, if radiators aren’t heating evenly this is one of the first things that display needing a little post-summer TLC. Most people know that radiators that are warm on the bottom but cold at the top need bleeding, but what if it’s the other way around?

A cold bottom but warm top indicates rust and sludge having built up in the bottom of the radiator; this prevents the water from flowing properly, and thus heating the radiator evenly. Luckily, a radiator that’s cold on the bottom and hot at the top is relatively easy to fix. Read on to find out how.

If Your Radiator Is Hot-Headed…

you can take these steps to remove the sludge:

Removing the radiator(s) and flushing the sludge through manually

This can be a very messy job but one that is easy enough to do. As the radiators will be full of sludge, you will need to make sure your carpets and floors are protected, and also be prepared to mop up any spills. For this you will need some old towels and sheets, and a bucket or bowl. You’ll also need seal tape, or ‘plumbers tape’, a radiator key and two wrenches with adjustable heads. To remove your radiator, first you must:

  1. Turn the central heating off and wait for it to cool completely down, otherwise you may have boiling hot water coming out of the pipes.
  2. Place the towels and sheets underneath the radiator(s), concentrating on the areas where the pipes come through the floor, and around the valves.
  3. Isolate your radiator(s) from the central heating system by turning off the valves. Start with the Thermostatic Radiator Valve. Turn it fully to its ‘off position’. Next you will need to turn off the Lockshield Valve: This is usually the one with the plastic cover on it. Remove the cover and turn the valve fully clockwise using one of the adjustable wrenches. Make a note of how many turns it took; this is because when you replace the radiator, you’ll need to reset the valve by the same amount of turns.
  4. Place a bucket under the thermostatic valve and use both the adjustable wrenches to loosen it.
  5. Ensuring that the bucket or bowl is still under the thermostatic valve, it’s now time to loosen the bleed valve. All of the water will come flowing from the thermostatic valve once you do this, so it’s imperative to make sure the bowl/bucket and sheets/towels are in place. Loosen the bleed valve using the radiator key.
  6. Use the radiator key to loosen the lockshield valve. You can tilt the radiator to get rid of any surplus water.
  7. Use the radiator key to close the bleed valve.
  8. Remove the radiator from the wall.
  9. As the radiator is probably still full of sludge, it’s a good idea to take it to an outside space to clean. Use a hose to flush any dirt and residue through manually.

This is a great way to clean one or two radiators, but if all of your radiators are affected, or you keep getting a sludge build up, then it’s probably a sign that you need to

Drain Down Your System:

Draining down your system involves a qualified plumber power flushing your central heating system with a strong cleaning agent, ridding it of sludge build up and helping to prevent it from happening again in the near future. Always employ the services of a plumber who is RGII registered, which means they are qualified to work safely with gas boilers and central heating systems.