Boiler Not Working? The Definitive Guide & How To Fix It

James Elston
Written by James Elston
Updated on 1st December 2023
Posted on 30th November 2023
Boiler Not Working: The Definitive Guide & How To Fix It

Combi boiler not working? Or system boiler and regular boiler broken? Here’s how to fix

If you are asking yourself the following questions, you are in the right place:

boiler not working
  • Boiler not turning on?
  • Has the boiler stopped working?
  • No hot water to taps
  • Radiators not getting hot
  • Do you have boiler problems and need solutions?

If your boiler has stopped working and you require a Gas Safe heating engineer, there are several different reasons why this may have happened. Even the best combi boilers and best system boilers can spring a leak. 

Is your Boiler not working?

Boiler Not Working?

If your boiler is not working and you have no hot water for a nice hot shower or to get warmed up after a freezing cold day, then in this guide, we are going to reveal everything you need to know about a broken boiler, a boiler which won’t ignite, how to fix a boiler and calling an engineer.

This guide includes central heating boiler problems troubleshooting, details on how to maintain your boilers to ensure that such situations do not happen again in the future, for example, cold weather, a boiler not working after a power cut, and repressuring a boiler for the water pressure.

With that being said for boiler help, continue reading to discover everything you need to know about repairs or replacement boilers

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Most Common Problems with Boilers

Several different issues are associated with boilers today and, therefore, many different issues that you may account for yourself.

Whether you have an old back boiler problem, a gas boiler not working or a recently installed combi boiler not working, you can always have boiler issues similar to what you can have with your car.

Boiler Not Working?

No matter the sort of problem, one important factor that you need to remember is just how critical it is to choose a Gas Safe registered engineer to deal with the problem.

One thing that you should never do unless you are trained is tried to rectify the problem yourself.

This may result in safety issues, or it is getting worse, meaning a bigger and more expensive problem on your hands.

However, not only this, but it is very dangerous to try and fix a gas supply boiler yourself without the required experience, even if you do think that the boiler repair that is needed is straightforward.

Video: Boiler stopped working?

In this video, we will explain all you need to know about a damaged boiler, a boiler that won’t ignite, how to fix a boiler, and when to call an engineer.

What are some of the Most Common Boiler Issues?

  • This includes no heat, low temperature and no hot water due to problems with low water levels. 
  • Issues with the thermostat or fuse box, failure of motorised valves/ diverter valve, and broken airlocks and diaphragms.

In addition to this:

You may also find:

  • Corrosion has caused this to occur, especially if your boiler is leaking around the tank or pipes.

Other common boiler issues include

  • The boilers switching themselves off which is also called a lock out, the boiler thermostat not working, and low boiler pressure.

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What kind of fuel does your boiler use?

5 Reasons why your Boiler may not be Working

Are you thinking can a boiler leak carbon monoxide when switched off? Or is it true a faulty boiler can be extremely dangerous, causing carbon monoxide poisoning?

Boiler Not Working?

Sadly the answer can be yes, this is why it is so important to invest in regular boiler servicing while also being aware of the signs that could mean there is something wrong with your boiler.

Before revealing the five key signs that your boiler needs servicing, it is imperative to stress that it should be serviced annually no matter what, as is the case with all gas appliances.

Also, your boiler will need an annual service to keep the warranty valid.

These yearly central heating checks will ensure that all of your appliances are in working order while any gas leaks or boiler problems will be repaired. All of the parts will be inspected, such as the pressure gauge, burners, pilot lights, and the boiler control panel in case anything is not working correctly.

Boiler Not Working?

These checks are critical; however, you shouldn’t merely rely on a yearly inspection, always do regular checks for boiler issues.

If you think that your boiler is not working or there is something wrong with your boiler you need to call the boiler manufacturer company a Gas Safe heating engineer as soon as possible so that you and your home is protected.


So, let’s take a look at five warning signs you should look out for when it comes to determining whether your boiler needs servicing. 

Boiler Not Working?

1)    The boiler is making noises it shouldn’t, banging or sounding like a kettle – If you have noticed some irregular noises coming from the boiler, you should turn it off and call your local gas engineer as quickly as possible. If the boiler won’t turn off just wait for the Gas engineer to arrive.

2)    The boiler is not heating water; the temperature of the water is not as hot as it should be / you are only receiving a little bit of hot water.

This indicates that your boiler is not working properly, which is why boiler servicing is recommended so that you can get to the bottom of the problem.

It may be that one of the parts needs replacing, the thermostat and the boiler not communicating or the boiler filling loop tap could be broken.

Boiler Not Working?

3)    The boiler pilot light won’t ignite, the pilot light frequently goes out – This also indicates that there is a fault with your boiler, and it often means the boiler heating will not work for this reason.

4)    No flame in the boiler, a yellow or irregular flame – If you notice that the flame does not look like as it usually should, then you need to turn your boiler off immediately and get an engineer to your property as quickly as possible.

A change in the flame can mean that carbon dioxide is present, so don’t use your boiler until it has been serviced. These gas boiler problems need a Gas Safe engineer as soon as possible.

5)    Soot or smoke stains are appearing on the appliance or near it – This shouldn’t happen and is a clear indication that your boiler needs servicing. Soot build-up can be dangerous, and there is the risk of carbon monoxide poison if you don’t deal with this issue.

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What if you cannot afford to replace your boiler that is not working? combi boiler not working

Don’t panic! Here at Boiler Central, we offer various boiler finance options for all new boiler options.

For example, if you have a combi boiler but the pilot lights have gone out, so you need to replace it, or if you are just interested in a combi boiler installation, but you don’t have the funds, you should consider boilers on finance whereby you will pay monthly for a new boiler. 

If you have a back boiler causing problems and you have heard the expense to remove it, again don’t panic because the finance options are still available.

Combi boiler installation can be expensive, around £2,000 to £3,000 for a Viessmann boiler, and not everyone has this type of money upfront.

Plus, if you’re not on income-related benefits, you can’t get help with combi boiler installation under the ECO scheme.

There is no need to let this dishearten you, as boilers on finance make life much easier.

Boilers on finance mean you can pay monthly for a new boiler, making the payment much easier.

With boilers on finance, it’s possible to spread the payment over a period of five to ten years.

When you pay monthly for a new boiler, your combi boiler installation will only set you back roughly £20 per month.

Sounds much more affordable, right?

Boiler Not Working?

Below, we reveal more about combi boiler installation and how boilers on finance allow you to pay monthly for a new boiler.

There are many benefits associated with combi boiler installation via boilers on finance whereby you pay monthly for a new boiler.

Of course, when you pay monthly for a new boiler, it makes the cost of a boiler installation a lot more manageable.

This is the main reason people consider boilers on finance.

It’s all about what matters to you when you opt to pay monthly for a new boiler. You can pay monthly on all types of boilers.

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What about a commercial boiler that is not working? why is my boiler not working

Commercial boilers are complex systems that have a wider range of issues that can go wrong. Commercial boilers can have more problems than your consumer boiler system for a standard home.

Nowadays we are becoming more and more aware of the damage which is being done to our planet.

We constantly remain of the detrimental impact we can be inflicting on our land if we pollute excessively.

Luckily, we are also becoming more and more aware of the different things we can do to reduce environmental damage as well.

Products are being released all the time, which are catered to effective emission reduction.

Boiler Not Working?

These are products we should all be made aware of to ensure that we have the necessary means to do our bit.

One product which is highly effective and highly recommended for those working with hot conditions is that of the gas ceramic filter.

This product has been created to reduce the emissions of gas.

Air pollution and the effects it can have are very much damaging and should not be ignored or undervalued.

A gas filter can provide those who work in a relevant industry with a fantastic method of ensuring that they are operating efficiently.

There are several different gas ceramic filters available on the market today, and when you look to purchase one, there are lots of things which you should be paying attention to.

First and foremost, you need to ensure that the filter works in the environment you are working in.

Some of the best filters can work in areas with up to 450 degrees of heat. This means that they apply to a wide range of skilled work procedures and needs.

Therefore, a top ceramic filter will be beneficial whilst in product recovery processes, as well as acid recovery, the production of nanomaterials, and biomass wood-fired boilers – to name but a few.

Once you have determined that the filter in question will operate effectively for your purpose, you should then concern yourself with how much reduction the filter can provide you with.

Every single filter you buy should come with a guarantee ensuring you that emission levels will definitely lower.

You should seek a filter which boasts a reduction in particulate emission to a level around 3mg/Nm3 and below.

Its importance of seeking a gas ceramic filter is something which cannot be underestimated. This is especially the case when you consider the new RHI requirements which have recently been outlined and must be followed stringently.

Moreover, with all the reports of the damage which is being done to our planet as of late, you must do your part to ensure that you are reducing emissions as much as you can.

If you consider all of the points in this article, then you should have no trouble finding an effective gas filter.

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What to do if your Boiler is Not Working – Your Free Fixes.

Finding out your boiler isn’t working is going to be a little panic-inducing but don’t worry!

frozen pipes

It could be a simple, easy to fix the problem. After some boiler troubleshooting, you may be taught how to fix a boiler online, or you may find you need a Gas Safe heating engineer to come and check your boiler which is broken or to solve the boiler problem simply.

There are many reasons why your boiler is not working such as a power cut, hot water not working after the gas turned off, boiler thermostat problems, frozen condensate pipe, issues with your gas supply, general cold weather or another problem with your boiler that is causing boiler breakdowns.


Some of the reasons below may be boiler problems which you can fix yourself without a heating engineer.

  • If your gas boiler doesn’t fire up, it could to do with the gas appliances. The homeowner regularly fixes gas appliances; however, if you are unsure to the reason your boiler is not working and you are not confident in fixing yourself, you should contact a company to help.

We now provide excellent boiler cover and one-off repairs for boiler breakdowns. Click the banner below to go to their website. 

What types of boiler breakdown is covered for your fixed price?

Boiler Not Working?

They cover Combi boilers (these are the most common boilers), system boilers and regular boilers.

So, without further ado, let’s look at the common problems that could be causing your boiler not to work that are easy to fix.

Did You Pay The Boiler Bill? 

Don’t laugh and think “well of course I did” because forgetting to pay your gas bill is easier than you might think.

Boiler Not Working?

If you have an automatic payment (direct debit) set-up, then a simple oversight could have caused your supplier not to be paid.

Or if it isn’t an electronic/ digital issue, then you might have just forgotten about it.

It can happen, and we’ve all done it at one time or another.

If you have a top-up/ pay as you go meter, then you might have forgotten to put some money on it as well.

Or it could all be your supplier’s fault, couldn’t it?

They aren’t exactly known for always taking their payment when they should are they?

So, if your boiler isn’t working, make sure everything is paid up, or money is on it.

You can then easily correct the issue and get your boiler working again.

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Is The Boiler Turned On? Boiler Not Working?

Well if you didn’t roll your eyes at the first possibility then you are definitely going to be doing it now, aren’t you?

But you might be surprised to learn just how common this issue is!

Believe it, or not, many people have fallen victim to this very thing. You might not even realise your boiler has an off switch in the first place or that the water pressure has gone.

Yes I know it sounds a little patronising, but it can happen so if your boiler suddenly stops working then be sure to check the on/ off switch.

A boiler can accidentally be turned off for several reasons it could be down to human error, an issue at the mains fuse box or any of the other possibilities.

So, before calling in an engineer just double-check the switch or fault codes, after all, it costs nothing.

Is It Down To Low-Pressure Problems? Boiler Not Working?

Okay so now we are getting on to less embarrassing issues.

Pressure basically means the balance of air and water in your boiler, there is more to it, but we are trying to keep things simple.

Your boiler needs a certain amount of pressure to work correctly, which you can measure by using the pressure gauge on your boiler.

A loss on boiler pressure will result in not enough water running through your boiler.

Now a boiler can lose pressure for several reasons, and it doesn’t always mean there is a serious issue like a leak or damaged component.

While that can happen, one of the most common issues with pressure is down to the natural use of water when running your home’s heating.

Now if you notice your pressure gauge is low, you can attempt to fix the problem by topping it up or to use the technical term repressurise it.

This might sound complicated, but it’s actually quite easy to do.

How to repressurise a boiler:

  • First of all, find the filling loop on your boiler you’ll be able to see it under the boiler, and it will often be silver in colour.
  • Every filling loop will have at least one black tap, but some do have two.
  • Simply turn these taps to repressurise the boiler, and when the gauge reaches the number 1 or green, safe zone turn the taps back.
  • Make sure the taps are safely locked back in their original position, or you’ll be having the exact opposite problem of too much pressure.

So, that’s how you check and fix pressure problems, and if you do it yourself, it’s free! Although you can always treat yourself for doing a good job if you want.

However, if you really don’t want to do it yourself (for whatever reason), then you can always call in an engineer to assist.

Still wondering why your boiler is losing pressure then read our guide as this will tell you about boilers losing pressure and how to fix it, even if it is leaking water.

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The Pilot Light Boiler Not Working?

That little glowing light in the boiler isn’t just for ambience, is it?

No the pilot’s light does an important job; basically, it’s a small internal flame that ignites the gas to heat the water.

If your boiler’s pilot light doesn’t light when your boiler is active, then you have a problem.

The good news (kind of) is that this issue is easy to spot, most people will quickly notice when their boiler’s pilot light isn’t working.

Fixing it could also be quite easy simply turning off your boiler and then turning it back on again could reignite the light.

Just like a crashed computer sometimes turning it off and on again can fix the problem.

The bad news is this might not work, the boiler might not turn off, or the boiler might not turn on and if it doesn’t you will need to call in a professional engineer to help you.

Sometimes a boiler’s pilot light can just go out like if a sudden breeze blows past for example. But in more serious cases it could be because of internal damage, but still, you lose nothing by trying the reset method do you?

The Condensate Pipe  condensate pipes

This is a seasonal issue as you will likely only have issues with your condensate pipe during the winter months.

Unless you live in a place with a very cold climate, of course, the condensate pipe travels from your boiler to the nearest outside wall so it should be easy enough to find.

The condensate pipe is where excess liquid (created by condensation) is collected and deposited. It drops outdoors in small drips and is susceptible to freezing during the winter.

If this does happen, then it will cause a blockage which as I’ am sure you can guess is not going to be a good thing and will cause a boiler lockout.

I mean when is a blockage ever good news?

frozen pipes

If the boiler has no escape route for the water (now that it’s blocked), it will essentially shut down.

Now, this might sound like a big problem but fixing the issue is easier than you might think!

All you need to do is gently pour some warm tepid (not hot) water over the pipe to melt the frozen blockage slowly. Once that is done, reboot the boiler, and it should be working again.

The Thermostat

Your boiler’s thermostat is a very misunderstood device in many ways.

A lot of people oversimplify things it doesn’t just give a temperature reading.

In fact, in more modern boilers the thermostat acts as an all singing all dancing control panel.

So, you can probably see where this going already, can’t you?

If this central heating thermostat is not working properly then your boiler won’t.

This can show itself in many ways, but usually, your boiler simply won’t power on. So, how do you fix this kind of problem? How to check if the boiler thermostat is working?

Well, it all depends on what the issue with the thermostat is.

If it isn’t charged, the batteries have run out, or your Wi-Fi isn’t working correctly then your boiler could simply not turn on.

Thankfully all these problems are quite easy to fix on your own.

It won’t cost you a thing unless you need to buy some new batteries, that is.

However, if the thermostat is damaged in some way, then you may need to call in an engineer to help you.

Boiler Not Working?

Or at the very least refer to your boiler’s manual for more in-depth guidance.

Boiler Not Working? – Certainly Not Free Fixes 

If your boiler isn’t working and it’s not a simple easy to fix the problem then bad news I’ am afraid because you might need to pay a lot of money to get things back in business.

How much things will cost can vary considerably but let’s look at the common problems with expensive solutions.


Low-Pressure Problems Again! Boiler Not Working?

Yes I know I talked about this before, but that was quite a while ago so let me briefly reiterate my point.

While low pressure can be fixed by repressuring your boiler which thanks to our handy instructions earlier, you should be able to do for free, that isn’t the only potential issue that can cause low-pressure problems.

Low-pressure problems that stop your boiler from working can happen for a variety of reasons.

Leaks and damaged components are two of the more common causes, and both of these problems will require professional assistance to fix.

Patching a leak can sometimes be quite cheap if it’s small and easy to get to (if it isn’t then expected to pay a lot more), but replacement components can be quite costly.

If you are suffering repeated issues with low pressure and things, keep breaking down, or leaks keep springing then it could be a sign your boiler is getting to old as well.

So, you might want to consider upgrading to a newer model. Don’t forget the finance options are available on all new boilers!

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Boiler/ System Leaks  Boiler Not Working?

Speaking of leaks, let’s talk more about them! Leaks in boilers come in two main forms system leaks and boiler leaks. Yes, I know it’s a little confusing, but I’ll explain.

A system leak means the leak could be anywhere within reason of course, often cause by higher pressure in the system.

If there is too much pressure in your system, your pressure release valve should stop this, however, if this is broken, it can cause pipes to burst.

Since a boiler is linked up to your home’s heating system, the leak could be near a radiator, at one of the main pipes leading out from your boiler or at a completely random spot in your home.

These types of leaks can be hard to track down although they are more commonly found at the joints in pipes.

A boiler leak is going to be a leak inside the boiler itself, so in most cases, it will be easier to identify and find.

Both system and boiler leaks will need professional assistance to repair or even find in some cases, which means you can expect to pay.

How much you’ll need to pay can vary quite considerably; however, the bad news is, either way, it won’t be free.

If you do get leaks repaired, make sure you keep an eye out for them in the future.

If leaks keep springing up, then it could be a sign that you need to get a new boiler.

My Boiler Simply Won’t Turn On.Boiler Not Working?

Why is my boiler not working? My boiler won’t turn on?

If your boiler just isn’t showing any signs of life and you’ve been through everything else on this list then oh dear.

This likely means it is an electrical issue which can mean many different things.

Some might be quite simple and easy to diagnose and fix, whereas others could take much more time and be much more expensive.

So, what can you do about this?

Well apart for the good old fashioned turn it off and turn it back on again method or saying a quick prayer you don’t really have many options but to call in a professional to inspect the boiler.

One of the most common causes of this is that the PCB board (as you can likely guess this is a circuit board) no longer functions.

But you might be lucky it could just be that a fuse needs replacing.

But even if it is simple, and easy to fix the issue, you will still need to call in an engineer to find out what is causing it and then pay to get the problem fixed.

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My Boiler Is Working But Doesn’t Heat Up.

Boiler Not Working?

Is the boiler not heating up? The boiler not working, no hot water?

Well let’s close out our look at the more costly repairs with this conundrum, shall we?

If your boiler looks like it is operating properly, but your radiators aren’t heating up, or there is no hot water from your boiler, then what should you do?

Well if it’s your radiators that aren’t heating up, then it likely means there is a blockage somewhere.

Again this likely sounds much worse than it is, radiators do pick up debris and dirty water and become congested over time.

An engineer will be able to fix this problem by carrying out a power-flush which will cleanse all your pipes and get your radiators working again.

Now if your boiler seems to be working okay but the water is running cold, then what should you do?

Call a home boiler cover company?

Well, this will usually be down to some internal component, not working. Most likely it will be the diverter valve which isn’t operating as it should.

The diverter valve is what moves water around to the different areas of your home.

An engineer will need to repair or replace the valve, which can be quite costly in some cases.

If it isn’t the valve causing the problem, then it could be several other things. But an engineer will be able to find the problem components with some searching.

Once they know what it is they’ll carry out any repairs or replacements needed.

So, that finishes up our (hopefully) helpful guide to what to look out for and do if your boiler isn’t working.

Yes, there is a lot to think about and consider, but if you’re lucky you might be able to get it working again on your own!

gas engineer

If you can’t, then professional help is always available.

If you need to get a new boiler, you can get a fixed online price and purchase your boiler online within 20 seconds by answering 9 questions!

If you are struggling to decide which size boiler fits your home, then read our guide on which size boiler fits your home.


So what should I do now with my broken boiler?

If you need help deciding whether to repair or replace your boiler that is not working, you can get a fixed price online for a new boiler within minutes. With low priced boiler deals and even cheap best combi boilers for those with less to spend, we will have a boiler for everyone. 

You can pay by card securely or opt for boiler finance with no deposit and up to 10 years in duration.

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Written by
James Elston
James Elston Director Of Boiler Central
Posted on: 30th November 2023

James Elston is our resident boiler and heating expert here at Boiler Central. With over 20 years in the boiler installation industry, James ensures that he knows everything there is about our Gas Safe boiler installations, energy saving and home heating solutioons. This can be from simply procuring the latest new boilers, to reviewing ensuring that Boiler Central maintains the highest standards across the workforce from office to your home.

Viessmann boiler

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