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Radiator Cold Spots, What are they?

radiator cold spots

Radiator Cold Spots

We install radiators to keep our homes warm; but when they develop cold spots (areas that feel cold to the touch, when they should be hot) they simply don’t generate the heat they should.  The temptation might be to just put the thermostat up to compensate but not only does this cost you more, you could even damage your boiler.  With a new boiler costing anything from £2,000 – £4,500 why take the risk when a little detective work of your own could help identify the problem?

If the radiator is cold at the top, it could simply be a case of air trapped in the system, in which case you could try ‘bleeding’ it to release the air and allow the system to re-fill.  This is a relatively easy job you can do yourself with a radiator key and a dry cloth. 

Start by turning the heating off to cool the system and then open the valve on the radiator with the key.  If there is air in the system, you’ll hear it hissing as it escapes – keep the cloth nearby to catch water which will appear once the air is all released.  Make sure you tighten the valve fully after bleeding to prevent leaks.  If you’re not confident of bleeding the radiators yourself; or it doesn’t cure the cold spots your boiler expert will be happy to help.

If it is the bottom of the radiator that’s cold, this could be a sign of ‘sludge’ building up in your heating system.  Over time particles of limescale, rust and even dirty water collect in the bottom of the radiator forming a thick sludge that can prevent the hot water from circulating properly.  As the blockage grows it will also slow down the supply of water to other radiators in your system and, eventually, it may cause damage to your boiler.

As soon as you notice any cold spots at the bottom of your radiator it’s time to call in your boiler expert to sort the problem out, usually by giving your system a ‘Powerflush’.  Over a period of 6 – 10 hours your heating engineer will use a pump/machine to push chemicals through your heating system at high speed.  This breaks up and dislodges the sludge, leaving your system clean and working properly again. Occasionally though, if sludge has been allowed to build up excessively, even flushing it won’t be enough to break down the sludge and you may need to replace the entire radiator.

As part of the Powerflush service; your boiler expert will also add a chemical inhibitor to provide a protective coating against future sludge build-up.  When the flush is complete, they will dispose of the contaminated water removed from your system, leaving you with piping hot, efficient radiators.

It makes sense to maintain your central heating system and keep it working as it should and a small investment now to prevent damage can prolong the life of your central heating system and save you a considerable amount of money in the long run. 

Most important of all is to have your boiler and system serviced annually; by doing so you should only need a Powerflush once.  If you live in a hard water area you could ask your boiler expert to add a Scale Reducer to combat limescale – one of the major causes of radiator blockages either as part of the Powerflush or as part of your annual heating service.  Another great way to protect against future problems is to add a Magnetic Filter; this helps trap debris before it enters your heating system.  The filter will be emptied routinely as part of your annual service.

Remember, your boiler expert isn’t just there for when things go wrong; we can give you practical advice to help you look after your central heating and keep it working well for as long as possible.

if you have cold spots or require more info on a powerflush just get in touch

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