How to fix a radiator that won’t warm up

There’s always one! And it’s usually the one that you’d really appreciate being warm when you crawl out of bed at 6am in the morning – you know, like the one in that icily tiled bathroom or the one next to the breakfast table.

This guide could help you diagnose and cure a radiator that is failing to heat up.

Common ailments

Is the radiator valve closed?

The handwheel valve that allows hot water into the radiator may be shut. Simply turn it by hand until it’s in the open position.

Have you checked the thermostat?

If your radiator has a thermostat, ensure that the valve hasn’t been set too low. If this valve is faulty or broken, it will need replacing and the central hating system will need draining.

Is the lockshield valve set correctly?

The lockshield valve is situated at the opposite end of the radiator to the handwheel valve. This one controls hot water flow into the radiator and may need adjusting if it’s not letting enough through.

Are the valves blocked?

Limescale can block valves and cause a radiator to stop working. If this is the problem, the radiator will need flushing out and the system may need to be descaled.

Bigger problems

Are the upstairs radiators not heating up properly?

This can be a sign that the feed and expansion tank in your loft has run dry, which could indicate that there is something wrong with the system on a larger scale.

However, it’s also possible that the ball valve in the tank could be blocked or jammed. If this is the case, removing the obstruction and refilling the cistern should sort it out.

Is the issue with the downstairs radiators?

This is an indication that the pump is faulty and will require the assistance of a Gas Safe Register approved professional.

Please remember

If you have major problems with your boiler or heating, it’s always recommended to seek the advice of a Gas Safe Register approved engineer, as appliances can be dangerous to handle.

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