How to manually flush a radiator and remove sludge

If you haven’t got a budget for getting a professional to power flush your radiators to remove radiator sludge and get your central heating system working again then the cheapest alternative is to simply do it yourself which is a fairly easy job if you’re used to DIY. This will involve removing the offending radiator and flushing it through with a hosepipe. Simple but effective.

This method is more of a stopgap and will only treat individual radiators and could leave sludge in your system so it’s not a long term solution but is a good alternative.

Tools for removing a radiatorWhat tools do you need?

To remove and manually flush your radiators you will need:

Guide to removing a radiator

This page has a detailed guide walking you though the actual process of removing a radiator. This can be done with one person but if it’s a large radiator then it may be worth getting someone else to lend you a hand. Most importantly make sure you follow all the steps and also take care to protect the flooring and carpet as radiator sludge is very very dirty.

Manually flushing a radiator

Here’s a pretty simple video guiding you through the whole process of removing your radiator and flushing it through, but wyou can read on for the rest of the guide.

Once you have removed your radiator then ensure you have a container ready to pour the contents in. This will be the water that is always in your radiator but it will be black and dirty due to the sludge build-up. The sludge will stay in the radiator though so this is where the flushing is needed.

flushing a radiator in the bathCarry the radiator outside to your garden and using a hosepipe flush clean water through the valve outlets on each side. This obviously hasn’t got the same pressure that power flushing has but it will do a good enough job to remove the radiator sludge. If you haven’t got a garden and perhaps live in a flat then you could always do this in your bathroom instead by putting the radiator in the bath, and then removing the shower-head attachment so that your shower is a replacement for the hosepipe. If you do use your bath then use an old sheet to prevent scratches on the bath and be prepared for some cleaning! See the image to the right!

Once you’ve flushed the radiator then you can reconnect it to your central heating system in a reverse of the way you removed the radiator.

A word of warning

This method is not very professional and if you have sludge in one radiator then it’s likely you have it in others so don’t view this as a long term solution. If left long enough then this sludge can make it’s way around your heating system and ultimately damage the boiler, heat pump and valves. If you have sludge in your radiators then it’s worth saving up to get your whole central heating system power flushed for around £300 and they will also add inhibitor to your system which should give your central heating a new lease of life.