How to Bleed Radiators 'Properly'

Bleeding radiators is important, regular maintenance everyone should know how to do if you have a central heating system. Follow me as I take you through each step of the way.

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[b]

Cheers, what I found was for the key is to zip-tie to the pipe at the first radiator!

[SN-szkw]

I love this channel. All the things my dad did, but never had time to teach me. 💗

[richard]

I always seemed to think that bleeding radiators was a huge messy job, but this really helped and I didn’t realise how easy it was! So thanks for that 👍

[MrMattlock]

I’m a keen fan of your videos Stuart, but as a heating engineer of many years’ experience, I’ve got to pull you up on a few points on this one:
You’re assuming everyone has a sealed (pressurised) system like yours. That’s not the case, there’s no such thing as a standard system in the UK. The first step is to understand what type of system you have. If you have a combi, or any system with a filling loop, or filling valves, then your advice is generally correct. But if you have a small tank in the loft, or at the high point in the system, then you have a vented system which is not pressurised and has no filling loop/point. There’s a lot of niche system designs about too, which are either pressurised, or unpressurised, but not so easy to identify.
When you do bleed the air out, make sure the system is off and cooled down to avoid scalding. Hot water at 1 bar pressure is no fun when it hits you!
Also, your comment that ‘air’ is what is causing the cold spot at the top of a radiator isn’t always true. Internal system corrosion causes gases which can give the same symptoms. These gases can be flammable too, so some caution is advised.
Unpressurised, vented systems can suffer from “overpumping”, where air is sucked into the system and collects at the top of radiators. My advice would be that if you’re regularly having to bleed radiators, then it requires investigation by an expert.
Lastly, if you have a removable filling loop hose, it shouldn’t be left connected. When you’ve repressurised the system, the valves should be switched off and the hose disconnected and stored where you can find it for next time you need it. I think leaving the hose connected contravenes water bylaws in some areas.

[jamowallace]

As someone who already knows how to do this, I can wholeheartedly say this is the perfect video for someone who has never done it before. Short, simple, yet detailed enough to get the points across
I salute you sir!!

[caroleberreur]

Super useful. We are useless at diy, and my husband was most grateful I found you. Very well explained. 😅

[agitgoztas]

ONE OF THE BEST DIY VIDEOS IVE EVER WATCHED.

[nickdawson]

For those without the modern fancy bleed valves I would suggest placing an absorbent cloth between the top of the rad and the wall as when the valve is loosened the water does not always dripped conveniently down. I have an older installation as many do, which is not pressurised so no need to look for that top up loop. Finally the “air” is more often actually the product of electrolysis between copper pipes and steel rads. Smell it!

[nialloc]

Great video. Did no know fully about the pressure that needed to be in the system. Once I sorted that all was perfect again

[boopo]

It now makes sense why I couldn’t get water out the radiator when trying to bleed it. I’ve now found what my issue is. Still need a plumber, but this will save me a few quid as I know exactly what needs doing, found a leak so know why I’m losing pressure, BIG THANKS!!!!

[pddotnw]

Thanks for uploading. This is a great instructional video, with clear and easy to follow guidance. Much appreciated.

[Alobger]

I’d add water from the mains first and all the way to the upoer limit of the pressure interval - in this case 1, 5 bar. Since the mains is at a higher pressure it will release a tiny amount of air when let down to 1, 5 bar. Then wait a couple of days before bleeding the radiators so you won’t have to do it twice.

[garynicholls]

Hi Gary from the UK here I just watched your video about the first quarter of it and know that you know what you're talking about, as I'm an old heating engineer DON'T forget to tell people to get the aluminium vent key and NOT the brass key as the brass key could damage your air vent on your radiator, and all I can say is well done Keep up the good work with the videos

[isyt]

Looks good. I was told by a gas safe engineer that the filling loop flexi cable should always be disconnected unless you are filling it up. I’ve never bothered disconnecting though.

[Quaker]

I knew how to bleed a radiator but not how adjust the pressure but now I do. Thanks for showing me Stuart with a clear, straightforward video. Brilliant!

[niazkhel]

The filling loop needs to be disconnected after use. After you removed the filling loop attach the caps on either end of the valves. This is so if the valves was to pass then your system will not get over filled and endup blowing off the Pressure relief valve on the boiler. Always get your boiler serviced yearly. Great videos. These help my customers from time to time

[rubypotato]

This video is great for people with normal radiators. I'd like to add something for people like me who bought fancy pants vertical radiators before knowing anything about bleeding the system. Sometimes the bleed valve is hidden on the back at the top and incredibly awkward to reach...AND a regular radiator key will not fit between the wall and the valve!! Finding a key that does fit is tricky but I ordered an ok one online. You have to bleed it blind, back to front and water spills down the wall no matter what! I would say don't bother but they do look nice!

[Loosehead]

Worth saying that radiator keys are available at DIY outlets and your favourite online retailer. Can never have enough.

[paul-fkde]

Thank you so much for doing this video this is definitely the best tutorial on how to do do this I have a radiator that's cold at the top and one that's cold at the bottom I never knew that you had to reppressure the system brilliant video thanks Stuart 😊

[zelekshadline]

Very useful - Thanks! All our radiators are now heating up properly. 😀