Even the most beautiful designer radiators are subject to basic chemical reactions such as rust and leaks. With central heating being reliant on water to make it work, unless you do something to prevent it, the water will inevitably begin to react with the steel.

The most common cause of corrosion in your radiator system is sludge, a black, mud-like substance which, if untreated, will build up over time. From the inside of your radiators, it will cause rusting which ends up eating tiny holes in the radiator resulting in leaks. However, your radiators aren’t the only part of the system that are potentially affected by sludge – it can cause damage to the boiler, pump and valves, as well as blockages in the pipework and heat exchanger.


As part of your central heating system maintenance checks, you need to look for signs of any build-up of sludge. Sludge is a problem not just because it’s the most common cause of leaks and rust in radiators, but also because it will affect fuel efficiency. And these days, we need our central heating systems to be as efficient as possible! 

Sludge is a black, mud-like substance. If it’s left untreated, it will get worse over time. The more sludge inside your radiators, the more likely it is that your system will start rusting, and this can result in tiny holes in the radiators. 

Your radiators aren’t the only part of the system that are potentially affected by sludge – it can cause damage to the boiler, pump and valves, as well as causing blockages in the pipework and heat exchanger.

In terms of the efficiency of your heating system, the more sludge you have in it, the harder it will have to work to keep your rooms at the required temperature. This means your energy consumption will increase and your heating bills will be higher.

How to prevent radiator corrosion

Whenever you replace your central heating system, make sure the plumber fitting it flushes it out in order to remove any debris and reduce the risk of corrosion. After the system has been flushed, a corrosion inhibitor needs to be added for extra protection. Although it will not prevent corrosion happening completely, it will certainly slow it down. To continue the protection, additional chemical treatments need to be added on a regular basis.

Alternatively, you could use a magnetic filter. Any iron oxide that develops in the system will be attracted to the magnet. After the filter is fixed, water will flow through it and any iron oxide crystals that have begun to form will be collected in it before they have a chance to do any harm.

Central heating systems can be cleaned with sludge removal chemicals or a power flush. Don’t forget to ask your plumber to then add a rust inhibitor or filter in order to reduce the chances of any rust returning.

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Finding the source of a radiator leak

If your radiator is wet, you’ve probably got a leak. The most effective way of identifying where the leak is coming from is to dry the radiator and watch to see where the water is coming from.

If the leak is coming from one of the radiator valves, try turning the valve off – when it’s fully closed, the leak will usually stop so at least you won’t have to worry about more water appearing whilst you call in the plumber.

Sometimes the leak will be in the place where the valve meets the pipe, and often it’s because the coupling nut has come a bit loose. Before you call out the plumber, try tightening the coupling to see if you can fix the problem yourself.

Sadly, if the leak is from inside your simple electric radiator, the most likely outcome is that you’ll have to replace the radiator.

If you need to replace your radiator, for whatever reason, visit our radiator showrooms in St Albans, Bristol, Leamington Spa, Clapham, Brighton or Islington to see our wide range of beautiful designer radiators which are not only aesthetically pleasing, they are also extremely efficient at keeping your room as toasty as you like it!