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Why is my radiator not coming on?

Just why is your radiator not heating up?

At this time of the year, there really is no bigger home heating-related nightmare than the central heating not working or a radiator not coming on (and trust me, I know, because as I write this my boiler is on the blink and I have to wait 3 DAYS until Baxi will send someone out to it).

But, putting my own problems aside for a minute, if you find that you have a radiator that isn’t working, what exactly should you do?

Well, before you panic (or freeze), there are a couple of things you can try to get it back up and running again (sadly, forcing the Baxi men to come under threat of execution isn’t one of them – I know that now, too).

Anyway, enough of that. How do you fix a radiator that’s on the blink?

What should you do if your radiator isn’t working?

When you notice that heat isn’t coming off a radiator, it’s very easy to panic and start to worry that there may be bigger issues at play.

And, if it happens in the depths of winter, it’s pretty safe to assume that you’re going to wonder how you are going to keep you and your family warm and get your radiator working again BEFORE the frosty nights really take hold.

So, let’s take a look at the problems you might encounter and how to fix them.

Check that your other radiators are working

If you come across a radiator that isn’t getting hot – before you go and tear it off the wall to try and fix the problem – go and have a feel of all your other radiators too.

If all your other radiators are not getting hot, that is probably a sign that a bigger problem is the cause.

a hand touching the top of a radiator

Check if anything unusual is happening with your central heating. It might sound a bit silly, but have you turned your heating on?

This is actually one of the more obvious things to check – but you’d be surprised how often it is overlooked, so it’s definitely one place to start.

Is the pilot light lit in your boiler, or is it malfunctioning? Is there hot water coming out of your taps?

If you have a combi boiler or a high-pressure central heating system, it could just be a case that the pressure in the system has dropped and the boiler has cut out.

boiler pressure gauge

Check that the pressure dial is in the range that is specified in the boiler’s instruction manual and top-up the water if necessary. There should be a step-by-step guide in the manual to do this, or you can find information in our bleed guide that can help you too.

If your boiler is on and the pressure gauge appears to be in the right place, but you’re not getting hot water or hot radiators, the chances are you’ll need to call out the professionals and get it looked at as soon as you can.

And when I say “as soon as you can” I hope you don’t have a three-day wait to look forward to, like I have had!

Can you tell I’m not entirely happy about that? Thanks, Baxi!

Clean your radiator

Now, I don’t mean on the outside of your radiator, though we have an amazing guide to doing that if you want to get those rads all spic and span.

What I mean is, if you feel the surface of a radiator and notice that it is warm at the top but cool at the bottom, it could be a build-up of corroded materials inside that is causing the issue and you’ll need to clean it out.

Here’s a quick guide to cleaning a radiator out, manually.

Close up of switch on brick wall
  1. Switch your heating off and wait for everything to cool down.
  2. Close the ‘lockshield valve’ so you can remove your radiator from the wall.
  3. Remove the ‘thermostatic radiator valve’ and open the bleed valve with your radiator key.
  4. Remove the radiator from the wall and tip out the content into a bucket.
  5. Take the radiator outside and spray a hosepipe through each of the inlets/outlets.

It’s probably important to mention that dirty water is going to come out of your radiator when you do this – so be sure to have towels or bowls and buckets around to catch the stuff as you’re taking it outside.

Do a thorough inspection of your valves

If the entire surface of the radiator is stone cold, the problem could lie with your thermostatic radiator valve. If you believe this to be the culprit, take its head off to check to see if the pin that operates it is still in full working order.

The pin should move up and down pretty freely and you’ll only need to give it a little tap if it is stuck in place.

a cross section of a trv with pin shown

Keep in mind that you will need to be careful when handling your TRV. If you try to use too much force when attempting to release the pin, you can cause damage that results in water flowing out of the opening.

If you do this, you will need to buy a new TRV.

Get Powerflushing

Sometimes, simply cleaning out a single radiator isn’t enough to get the system back into tip-top working condition.

When this happens, there is only one course of action for you to take – the dreaded powerflush.

Now, you can do a powerflush all by yourself if you’re the sort of person that likes to get their hands dirty, but it’s probably best to leave it to the pros.

A powerflush works by attaching a unit (like the one above) to the piping of your central heating and pumping clean water into the system.

This should force all of the dirt and debris from the out of your radiators and means you don’t have to remove any to get the job done.

A standard powerflush should take around 5 hours to complete, but we do highly recommend getting a professional to do the heavy work.

You’ve tried everything!

If you’ve done all of the above and you still can’t seem to get that radiator hot, perhaps it’s time to move to a new house!

Only joking.

If you have gone through the list above, though, and still find your radiator(s) is not getting hot, the best thing for you to do is to contact a professional heating engineer.

An experienced engineer is likely to have seen most of the central heating radiator problems before, so a good one should be able to diagnose the malfunction pretty quickly.

To find a good quote in your area, there are loads of places to look, but if they are working with gas central heating, be sure to use a fully qualified and registered Gas Safe Engineer.

Good luck with your radiators, but remember…

Of course, we wish you all the very best with fixing your radiator problems, but if you just can’t seem to get it sorted or even if you just fancy a change, pay us a visit and get your hands on some amazing radiator and towel rail deals at the UK’s leading designer radiator specialist.

Everybody should love their radiators, and you should be no exception!

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