How to reset your boiler

Has your heating suddenly stopped working? No hot water coming out of the taps, and you’re not sure why? Your boiler could have gone into ‘lockout’. Here you can find out how to reset your boiler.

Lockout is when your boiler shuts down because it has found a problem. The good news is you might not need an engineer if you’ve got a common fault.

In our step-by-step guide, we’ll explain why you might need to reset your boiler, and how to do it. And remember – keep reading if you’re still having problems after resetting.

When to reset your boiler

There are 2 reasons why your boiler might have gone into lockout.

• There’s a fault that won’t let the boiler work correctly (in this case, it’ll usually show an error code)
• There’s a fault that makes it unsafe for the boiler to keep working, e.g. high pressure or a problem with your gas supply

Resetting your boiler without fixing the problem won’t do anything. So first, you need to work out what’s wrong.

Why your boiler has gone into lockout

Your boiler will probably show an error or fault code. It usually appears on the display, starting with an ‘E’ or ‘F’. To find out what the code is telling you, take a look in the boiler’s manual.

Here’s what to do if your boiler has:

1. Low or high pressure

Your boiler might lock out if the water pressure is either too high or too low. The pressure gauge on the front of your boiler should usually be at around 1.5 bar. Anything below 1 bar is low pressure. And anything over 2.5–2.75 bar means the pressure is too high.

To fix this, follow our guide on how to repressurise your boiler.

2. Sludge or debris

You might notice that your boiler sounds noisier than usual. If so, it could be a build-up in the system. Limescale can interfere with your heat exchanger and other important parts of the boiler, stopping it from working properly.

Try clearing out the pipes with a power flush.

3. Ignition problems

Most boilers will lock out if they’ve failed to ignite 3 times in a row.

This could be happening for a few reasons:

• A fault with your gas valve
• Low gas pressure
• Trouble with your ignition lead 

If your boiler isn’t firing up, it’s best to call in a professional. Even if you don’t have boiler cover, we can set you up with our most comprehensive plan and repair your existing fault.

How to reset your boiler

Once you’ve fixed the problem with your boiler, it’s time to reset it.

For most boilers, all you need to do is press and hold the reset button for up to 10 seconds. You’ll know it’s worked if you hear your boiler firing up again, or if you see:

• The flame ignite
• The error code disappear
• A red/orange light turn green
• A ‘burner’ light turn on

The location of your boiler’s reset button will depend on the model. So here’s a breakdown of how to reset different gas boilers.

And again, if it doesn’t work or if you’re having to reset your boiler regularly, then call a Gas Safe engineer.

How to reset a Worcester boiler

See a flashing red light? This usually means your boiler’s gone into lockout.

If your Worcester boiler has a reset button:

1. Press and hold the reset button
2. Release it after 3 seconds

If it has a reset light:

1. Turn the temperature dial towards the reset light
2. Leave it there for 3 seconds
3. Turn it back to its starting position

How to reset a Vaillant boiler

If you have a Vaillant ecoTEC boiler, the reset button should be just underneath the display. To reset it, press and hold the button for one second. If it hasn’t worked after 3 tries, it’s best to call an engineer.

How to reset a Baxi boiler

Baxi boilers can be reset in 3 different ways, depending on the model you have. 

If your Baxi boiler has a reset button:

1. You’ll know your boiler is in lockout when you see a red light – either flashing or always on
2. Press and hold the reset button until the red light turns off
3. You may then see a burner light switch on, to show your boiler has fired up again

If your boiler has an ON/OFF/SELECTOR switch:

1. Open the front panel of the boiler
2. You might see an error code, or a flame failure light if you have a boiler without a display screen
3. Turn the selector switch to the R (‘reset’) position
4. Hold for 5 seconds before letting go
5. The error code should change, or the flame failure light should stop flashing
6. The burner light will turn orange to show that your boiler is working again

If your boiler uses a thermostat control knob to reset:

1. You’ll know your boiler is in lockout when you see a red light – either flashing or always on
2. To reset it, turn the temperature control knob anti-clockwise, all the way
3. Hold it there until the red light goes out
4. Turn it back to your normal setting
5. A burner light should come on to show that your boiler has fired up again

How to reset a Vokera boiler

If your Vokera boiler needs resetting, you might see a flashing red light.

Move the mode selector switch to the ‘OFF/RESET’ position, then move it back to where you would normally have it (either ‘hot water only’ or ‘heating and hot water’). You should see a green light if it’s worked.

How to reset a Glow-worm boiler

Glow-worm boilers tell you about problems by showing fault codes, which begin with the letter F.

To reboot a Glow-worm boiler, press the reset button, then wait 5 seconds. You should see your boiler start up again.

If your boiler won’t turn on after resetting

Remember, resetting won’t solve the problem. It’s just a way to reboot your boiler once it’s sorted.

If your boiler reset button isn’t working, check the power and pressure gauge again. If you’ve tried fixing and resetting it with no luck, it’s time to call in the experts.

If your boiler keeps going into lockout

There might be something wrong with your heating system if you keep having to reset your boiler. If you’re getting a lot of error codes and your boiler locks out after you reset it, then it’s best to book an engineer.

How to reset your boiler when the gas runs out

If you're a Pay As You Go customer and your boiler has a digital display, it’ll show an error message to tell you you're out of gas. Once you’ve topped up, reset your boiler by following the instructions above. The error message should disappear, and your boiler will work as normal.

If you have a mechanical boiler, we suggest contacting one of our boiler engineers.

Find out more about common boiler problems, and how to use your boiler timer.

Is it time for a new boiler?

Getting a new boiler is a big decision – but it’s usually worth it in the long run.

With an A-rated boiler from CORGI HomeHeat, you could save up to £630¹ a year on your energy bills. A friendly Gas Safe engineer will set everything up, and they’ll even throw in extras – like a free smart thermostat from tado°. So if you’re ready to make the switch, get a quote online in just a few minutes.

For more information, read our explainer on types of boiler.

Get a boiler, plumbing, heating, or electrics repair with Home Recover

At OVO, we want to be there for you in an emergency – whether you’ve got cover or not.

If something goes wrong with your boiler, plumbing, or electrics, we’ve got you. With Home Recover, we’ll fix it for free for OVO customers (or £79 if you get your energy elsewhere) when you take out our Complete cover plan afterwards².

Our experienced, independent network of engineers is already trusted by over 200,000 UK homes³. And with our 24/7 emergency helpline, we’ll help you get up and running again as soon as possible.

Sources and references

¹ According to the Energy Saving Trust (July 2023), a detached household moving from a G-rated boiler to a new A-rated condensing boiler with a programmer, room thermostat and thermostatic radiator controls (TRVs) could save up to £630 a year. Savings will vary depending on the size and thermal performance of your home. Here are their calculations.

² Exclusions, eligibility criteria, cancellation fees, and terms and conditions apply.

³ OVO Energy and CORGI HomePlan are part of the OVO family, and as a group serviced 215,927 boilers in 2022.