August 10, 2021

Bleeding Your Radiators: Homeowners Guide

How Do I Know When My Radiators Need Bleeding?

If you find the heat output from your radiators is lower than you’d expect, then you may need to consider bleeding your radiators. The main tell-tale sign is feeling the top of your radiator, then comparing it to the feel of the bottom of your radiator. If the top of your radiator is colder than the bottom, then it is definitely time to bleed your radiators. Keep reading our in-depth guide on how to bleed your radiators.


Where To Start When Bleeding Your Radiators

If your house has two levels, start bleeding the downstairs radiators first. When it comes to heat distribution, the radiators, which are farther away from the boiler, are recommended. You’ll need to bleed the radiators on the first floor before you go on to the radiators on the second floor, which are furthest away from the boiler.

Please note that before you start the process of bleeding a radiator, make sure the central heating system is turned off. Please keep this in mind, since a small percentage of water pumps (depending on where they are installed in the system) may suck in air into the radiator, causing a negative impact on the heating system when the bleed valve is opened.

Bleeding Your Radiators

How To Bleed Your Radiators

You will need a radiator key, a dry cloth or towel, and a container to collect any water that leaks out of the radiator. You can get them in any DIY store, and they will typically cost between 50p and £3. It is possible to use pliers, but the risk of damaging the valve means a suitable key is absolutely required.

Make sure the central heating is switched off before you begin. Never turn on the central heating when bleeding radiators, since boiling water will erupt from the radiators.

A square with a red ‘bleeding screw’ on top of the radiator is called a bleeding square. That section has to be rotated in order to open the radiator cap and discharge the air and water inside. In order to collect any water that pours down from above, place your container on the floor under this location.

Turn the bleed screw clockwise. An hissing sound should be heard when the air exits, and the cloth should be used to collect any wetness.

The radiator is completely drained when the hissing air ceases and there is a steady flow of water. To tighten the bleed screw, use the key, but avoid tightening it too much since you may harm the valve.

Follow this procedure: Wipe off any water that dripped on the radiator with a damp cloth to prevent corrosion, and then go to the next radiator, wiping it down and starting again.

After the radiators have all been bled, you may switch the heating system back on. Make sure the heating system is in the proper pressure range and turn it on to see whether the radiators are heating evenly and there are no leaks from the radiator.

Sometimes, radiators may need to be bled more than once. If the issue remains, it may be necessary to have a professional engineer do an inspection of the system.