Tips to fix a cold radiator, learn how to balance your radiator

Cold radiators in different parts of the home

Cold radiators in different zones


If the radiators aren’t working in certain parts of your home it’s likely there’s a fault with one of your central heating system’s zones.

A predetermined area of the home, different zones enable you to control the temperature in different rooms.

In order to find out what’s causing certain radiators to stay cold, follow the steps below:


Get a new boiler quote   


  • Check your zone timer or thermostat

In order to rule out a problem with your timer or thermostat, check the controls in the zone where the radiators aren’t working.

Your manufacturer's manual will provide details on the correct settings.


  • Check the zone valve

Controlling the supply of hot water to the radiators, if the open and close valves are faulty you’ll need to contact your local heating engineer.


Cold radiators upstairs


If you find that the radiators on the upper floors of your home are cold it’s likely that there’s a problem with the feed and the expansion cistern.

In order to check what’s causing the problem, follow the steps below:


  • Locate the cistern, which will usually be found in the loft.


  • Ensure there’s enough water within the cistern to enable the ballcock to float. But be careful not to fill it completely. 


You should now notice that the radiators start heating up normally. If for any reason heat doesn’t return to the upper floors of your home, contact your local heating engineer.


Cold radiators downstairs


If you find that the radiators on the lower floors of your home are cold it is likely that there’s a problem with your pump.

In order to repair or replace a faulty pump, contact your local heating engineer.


Just one radiator stays cold


If you find that one radiator within your home stays cold ensure that the valves located on the sides of the radiator are open.

If the valves are open but the radiator is still cold it’s possible that the valves are blocked.

If you have an open-vent system (a conventional central heating system which is un-pressurised and tank fed), you can use a heating system sludge remover that can be bought at most DIY stores.


You can flush the system yourself by:


  • Adding the liquid to the feed and expansion tank.


  • After a few days you'll need to empty and refill the system.


If you have a non-open vent system you’ll need to flush your radiators with a hosepipe.


Get a new boiler quote   


Information and other materials on this website are not intended to constitute professional advice and should not be relied upon. Please see our Terms of Use for further details.

Related articles

Bleeding a radiator

How to bleed a radiator

Bleeding a radiator is an easy and cheap fix for combatting cold and patchy radiators. It's something anyone can do in their own home without the need...
Cold patched on a radiator

How to fix cold patches on radiators at the top, middle or bottom

Cold patches appear on radiators when your water supply is unable to properly flow through your central heating system due to air or substances such...
Central heating home guide

5 Energy saving tips to make the most out of your central heating

While the lifespan of the average boiler is 12 years, it’s important to maintain it regularly to ensure maximum longevity. If your boiler and central...