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:


  • 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.

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