Eco Happy (Solar Expert)

Published February 23, 2024

When your boiler shuts down unexpectedly, it’s typically a sign that your boiler has experienced a lockout – an emergency shutdown feature when your boiler detects an issue in its system.

Your boiler is essential for your central heating system and hot water. So, if your boiler stops working, you need to know how to reset it, what the boiler faults mean, and what that flashing boiler light is yelling at you. However, it’s vital that you reset your boiler safely, without causing damage to yourself or the system.

That’s why we have put together the most important steps to help you walk away unscathed. This guide will give you easy, clear, and actionable steps to help you reset your boiler safely and get that hot water flowing again.

What Is Boiler Lockout?

In modern boilers, manufacturers implement a boiler lockout safety feature that kicks in when there is a fault in the system. You may see your boiler light flashing red or green with a boiler error code, which could indicate a lockout.

The fault code displayed could also provide the actual cause of the lockout. Without the lockout feature, there could be extensive damage if the problem is severe enough.

Why boilers stop working

There could be several reasons why your boiler could have stopped working. It is important to understand why this is happening before you reset your boiler. It stopped for a reason, and if the reason is not resolved, this could cause further damage.

The issues that could cause a lockout include:

  • Water pressure: If the boiler pressure is low, your boiler could lock out. Check the pressure gauge on your boiler. If it is below 1 bar, you probably have low pressure. Check for leaks in the pipes and radiators, as this could be the source of the drop in water pressure.
  • Ignition failure: If your boiler doesn’t ignite when you turn it on, there may be an ignition failure or gas supply issue. Check that the gas supply valve is open and for any smells of gas.
  • Overheating: An error code will pop up to show if your boiler is overheating. There could also be unusual sounds coming from the boiler, and your radiators would be too hot to touch. Check for blocked air vents, bleed your radiators, and ensure there is proper circulation for the water.
  • Blocked components: If there is reduced water pressure, but your pressure gauge says it is normal, there could be blocked components. Check that all radiators are hot, not just some.

Resetting Your Boiler

Safety is paramount when it comes to fixing your boiler. Remember, you are dealing with hot water and gas. If mistakes happen, you could get badly hurt.

Take note of these important tips:

  • Leave any gas fixes to a Gas Safe engineer to fix.
  • Don’t reset your boiler during a power outage.
  • Watch the pressure gauge. If the pressure is too high or too low, it could mean trouble.
  • Use your senses – smell for gas leaks, and listen for gurgling sounds or banging.
  • Keep your boiler system maintained with an annual boiler service.

It’s also a good idea to consult your boiler-specific manual for any safety recommendations when you reset your boiler.

Steps to take

First, locate the reset button. The reset button is usually found on the front of the boiler, on or near the digital display screen.

Generally, to reset your boiler, you would press and hold this button for around 10 seconds. Just keep in mind that the full reset will take longer to complete.

Follow your boiler manual for the precise amount of time needed to hold the reset button, as different boilers may have different time requirements.

Basically, it is a matter of pushing, holding, and waiting. Just be careful not to accidentally push the button multiple times or let go before the allotted time.

Brand-specific steps

Baxi boiler

Your Baxi Boiler could have a reset button, reset knob, or double-button reset option. Each boiler has slightly different reset instructions.

  • Button: Press and hold the reset button, which is found under the display screen. Press it for no longer than two seconds.
  • Knob: Turn the circular central heating control to the reset position. Hold it in this position for three seconds.
  • Double button: Press the green reset button on the right and hold it in for five seconds. The button to the left will then flash red quickly before it starts to reset.


With an Ideal boiler, simply press the reset button for one to two seconds, and the boiler will reset.


On a Vaillant boiler, the reset button has a flame with a cross through it. Just press and hold the reset button for a couple of seconds to reset your boiler. You can refer to the Vaillant boiler manual for more information on the issue.

Worcester Bosch

To reset a Worcester boiler, press and hold the up and down buttons at the same time, which are found on the right-hand side of the display, for five seconds. If the issue that caused the boiler lockout is resolved, the boiler will work again. If not, an error code will appear. If you reset the boiler too many times, a fault code will result, meaning you need to call in a Gas Safe engineer.

Troubleshooting After A Reset

If you follow the steps to reset your boiler and it still pops up an error code, you need to take note of what the code represents- this should be in your boiler manual.

If the boiler does not restart after the first reset, you can try again. However, it’s advised that you don’t reset your boiler more than three times in total. If you press the reset button multiple times, you could end up damaging the control panel.

Instead, if you have tried a reset and it didn’t work, it’s best to call in a qualified heating engineer to assist.

If there is a fault code, refer to your manual. It may have been caused by something simple, like a power outage. However, it can also be something like a faulty pump, a blocked heat exchanger, or a leaking system. If you are unsure about the cause, then rather call in a professional heating engineer to assist.

Frequency of boiler resets

Sometimes, a simple boiler reset will resolve a glitch. But if your boiler requires frequent resets, then it means there is an underlying problem that needs to be resolved. If the issue persists, it could cause damage that will be costly to repair.

It’s best to call in a professional heating engineer to resolve these types of issues. Eco Happy will gladly help with personal advice or a quotation.


How to reset a boiler without the boiler reset button?

Boilers without a reset button are typically older models. These generally tend to have a reset function under the front panel of the boiler.

What is the crossed flame on Vaillant boilers?

The crossed flame on a Valliant boiler is the reset button. Press this button and hold it for a couple of seconds to reset your boiler

Why would a boiler need resetting?

A boiler can glitch or produce a false reading. In these instances, simply resetting your boiler should solve the problem so that your boiler functions as normal. However, if your boiler continues to lockout, there could be a pressure, flow or temperature problem that needs to be resolved before the boiler can be reset.


If you have followed your manufacturer’s guidelines, checked everything, and tried the boiler reset button to no avail, there may be a deeper problem to address.

So, if your heating system is still giving you trouble, it may be time to call in a professional. You are welcome to contact Eco Happy for assistance.

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