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  • Gastech Heating And Plumbing

How To Bleed A Radiator


Some heating and plumbing problems can be solved quite easily if you know how. If your radiator doesn’t seem to be heating completely and you can feel cold spots on it, then it isn’t working properly and you are paying for central heating services that you’re not getting! Sometimes this can be solved quite easily by bleeding the radiator, resulting in a cosier home and a happier family. So, if your radiator isn’t warm all over, here are the steps to follow to solve this:


What you will need

  • A radiator key or a flat-head screwdriver

  • A bowl and/or some clothes

How to do it


1. Turn on your heating

Firstly, turn on all your radiators and leave them to heat up fully before moving on to the next step. This will help the pressure build and release the air, and it also lets you check which radiators need bleeding. You’ll know which ones are fully working and which ones are not.


2. Find out which radiators aren’t working

Go through your property and check each radiator to check for cold spots, particularly towards the top of the radiator. Be careful of burning yourself – those that are in working order may be very hot. Those that have cold spots may need bleeding.


3. Turn off your central heating

When you have checked each one and identified the radiators that need bleeding, turn off your central heating. This is important so that you don’t burn yourself (or anyone else) and to prevent water from getting everywhere. Also, if the radiator isn’t completely cold, any water that comes out whilst bleeding it could be boiling hot.


4. Bleed the radiator

Leave the radiators to cool first and then you can start your work. First, look for the valve at one end of the top of your radiator. Place the radiator key in the square part in the centre, or put the end of a flat-head screwdriver into the groove. You can use a cloth to hold the key in place and another cloth of bowl to catch any drips whilst you slowly turn the key anti-clockwise for around half a turn. A hissing sound will emerge if gas leaves the radiator. Hold the key/screwdriver until the noise stops and water starts coming out.


5. Close the valve

The valve needs to be closed as soon as the water starts coming out. So when the hissing noise stops, close the valve then. The water may come out as a dribble or a pour so you’ll need to act fast. You can damage the valve by over-tightening it, so be gentle.


6. Check the pressure

Check the pressure by looking at the level on your boiler. If the pressure is too low, top up the water using the lever or tap on your boiler (the ‘filling loop’). You can find out the optimum level in your manufacturer’s manual and it will also guide you on how to re-pressurise your boiler. If you have any problems, simply give Gastech heating and plumbing a call, and we’ll be happy to help.


7. Check the radiators

Turn your heating on and check for any cold spots when the radiators have heated up. Also check that the valves aren’t leaking.


Plumbing Services

It may take a couple of times before you complete the bleeding process but if it doesn’t appear to be working, call in the professionals. It could be a bigger problem in your system. Gastech Heating & Plumbing can assist with boiler installations and repairs and plumbing services so you can put away the tools! Call us today on 0800 975 2180.

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