A boiler lockout can occur at the worst possible time, like when you’re about to run the kid’s baths or are in the depths of winter.
If your boiler has failed to ignite despite several attempts to turn it on and is leaving you in a cold home with no hot water, you may be experiencing a boiler lockout.
Unless you enjoy sitting in cold rooms or taking cold showers, you must determine why the boiler isn’t igniting and fix it. Your heating system won’t work until you do.
If you’re wondering what can cause an ignition lockout on a boiler and how to fix it, don’t panic. Millions of homes in the UK use boilers and an ignition lockout is a common issue.
This guide will cover the most common faults that can occur and cause a boiler ignition lockout. You’ll also learn how to fix an ignition lockout on a boiler by resetting it and how to get it running normally.
As with any boiler issue, if you have doubts about the cause or have no confidence to investigate, always call a qualified heating engineer for assistance.
Wondering which boiler manufacturers performed best? Check out our best boiler brands guide for the full rundown and if you are trying to determine who the best boiler installation company is, check out our Warmzilla and Boxt reviews.
Why Is Your Boiler in Lockout?
A boiler lockout is a safety feature that kicks in when your boiler detects a fault in the boiler or the central heating system.
Your boiler will automatically initiate a lockout or a shutdown procedure because:
- There is a fault preventing the boiler from working correctly or
- There is a fault making it unsafe for the boiler to continue operating, like a problem with your gas supply or high pressure.
A boiler ignition lockout can help prevent an issue from escalating and causing damage to internal components.
It also prevents other safety risks that can occur if it continues operating, such as a boiler explosion or fire.
How do You Recognise a Boiler Ignition Lockout?
The first sign is your boiler not firing up. Your boiler will also let you know if there are any issues.
If you have a new model with a display panel, it will show an error or fault code, usually a number or string of letters and numbers. Older models can show red or green flashing lights.
The code can help you determine what happened so you can fix it. Codes can differ depending on the model and brand of your boiler, so ensure you have the boiler manual handy.
The manual will contain a list of all possible fault codes and explain their meanings to help you identify the cause and the right course of action.
The table below shows examples of fault codes from an Ideal Logic boiler:
| Fault Code | Description | Solution |
| L2 | Ignition Lockout | Check the gas supply and pilot light; consult a qualified engineer if unresolved. |
| F2 | Flame Loss | Check the gas supply and pilot light; ensure the gas valve is open. |
| F1 | Low Water Pressure | Check and refill the boiler to 1.5 bars; repair any leaks. |
| L6 | False Flame Lockout | Reset the boiler; check the flame detection mechanism. |
If you can’t find the boiler manual or it doesn’t contain the fault code, you can visit the manufacturer’s website or search for the code for the boiler’s make and model online.
You can also contact the manufacturer if you have an older model that doesn’t show fault codes.
How to Do A Reset When Your Boiler Locks Out
The first thing you can do when you experience a boiler ignition lockout is try resetting the boiler according to the manufacturer’s instructions.
Modern boilers usually have a reset button on the display panel or somewhere near it.
You may need to press and hold the reset button for up to 10 seconds before releasing it to allow the internal parts and processes to activate and restart.
Older boilers may not have built-in reset features, so you may need to consult your boiler manual to learn how to restart the device.
If the boiler doesn’t reignite following the reset, it means the fault is still in play, and you need to identify the root cause and address it.
Do you need a new boiler and want to know which boiler brand is best? Check out our best boiler brand guide, and the best combi boiler models currently available.
How To Reset A Valliant Boiler
The reset button on most Valliant boilers is found on the control panel, below the digital display. To reset:
- Press and hold the reset button for 6 to 8 seconds.
- Check if you can hear the boiler working or if the flame has ignited.
- If an error code was displayed before resetting, check to see if has cleared.
If the boiler fails to restart or the error code still displays, contact a Gas Safe registered engineer.
How To Reset A Baxi Boiler
Baxi boilers usually show a red that constantly flashes or illuminates when your boiler enters lockout. To reset:
- Press the reset button until the red light disappears.
- You can also turn the temperature knob fully anticlockwise.
- Hold the knob until the red light disappears, and turn back to the desired setting.
If your boiler uses a switch:
- Turn the switch to the R (Reset) position.
- Hold for 5 seconds and release.
- The error code should be replaced by the boiler’s temperature reading.
How To Reset A Glow-Worm Boiler
The reset button on a Glow-Worm boiler is usually a red button located on the front or side of the boiler. To reset:
- Press and hold the button for 10 seconds.
- The boiler should start up again.
- Call a registered engineer to diagnose the issue if it doesn’t restart or the fault code persists.
How To Reset A Vokera Boiler
A red light will start flashing when a Vokera boiler encounters a fault or goes into lockout. To reset:
- Find the mode selector switch.
- Turn it to the OFF/RESET position.
- Turn it back to the ‘heating and hot water’, or ‘hot water only’ position.
- Allow at least 2 minutes before turning back to the reset position.
If you constantly need to reset the boiler, it may have a fault. Using fault codes, you’ll need to figure out the cause and fix it or call a registered engineer.
How To Reset A Worcester Bosch Boiler
- Press and hold the reset button on the boiler’s control button.
- Hold the button down for 3 to 5 seconds.
You can also use the feature light to reset it through the following steps:
- Turn the dial down until you reach the reset light
- Hold for 3 to 5 seconds until it returns to its original position.
How to Fix a Boiler Ignition Lockout Caused By:
Understanding the root cause can help you identify how to fix an ignition lockout on a boiler.
Below, we discuss how to fix the most common faults that result in a boiler lockout:
#1 Faulty Boiler Pump
The pump inside your boiler can develop a fault due to a blown seal, seizing up, or a blockage caused by debris.
Don’t try to fix the faulty boiler pump yourself if the error code displayed on the boiler signals a heat pump fault.
Contact a Gas Safe-registered heating engineer to assess the pump’s condition safely and advise on the next steps.
Did you know that your boiler’s efficiency can impact the amount of energy it uses and ultimately impact your heating bill costs? Check out our guide to the best condensing boilers if you want to learn more.
You may also find our review of the best eco-friendly boilers of interest.
#2 High or Low Water Pressure
Boilers need the right amount of water pressure to function properly, and the pressure shouldn’t be too high or too low.
Most boilers operate at pressures between 1 and 1.5 bars, and you can refer to your manual to learn the correct pressure for your boiler.
If the pressure is too low or too high, the boiler can initiate a lockout to protect the internal parts from damage.
You can fix it by using the filling loop to increase your boiler’s pressure if it’s too low, but ensure you consult the manual for further guidance.
A leak in the system can also cause pressure loss, and you’ll need a Gas Safe registered engineer to fix it.
If the pressure is too high, you can reduce it by bleeding the radiator valves. If unsure, check the manual for instructions or watch online videos.
Got a common boiler problem? Check out our quick fix guide for boiler lockout, boiler ignition faults, boiler PCB faults, faulty diverter valves, and boiler timer issues.
#3 No Electric Supply
Boilers need a small amount of electricity to ignite.
A boiler ignition lockout can occur due to a loss of power caused by a local outage, blown fuses, or a tripped switch within the property.
You can fix it by ensuring all fuses are working and that the switch where the boiler is connected is on.
In rare cases, the power outage may be traced back to the boiler’s Printed Circuit Board (PCB). You may need to replace it to ensure all electronic components work safely and efficiently.
#4 System Blockage
System blockages from debris or sludge accumulation in the boiler, radiators, or pipework can cause a boiler ignition lockout.
It can also result from frozen pipes in the winter months or on cold mornings. Limescale can also build up and block the boiler’s heat exchanger and other components.
You can easily fix it if it’s a frozen pipe, and you can defrost it manually. Otherwise, you’ll need to hire a professional heating engineer to investigate the cause safely and flush any sludge or debris from the system.
Sometimes, blocked parts can be cleaned, but damage may have occurred, and you may need to replace them.
#5 Ignition issues
Three unsuccessful ignition attempts can also lead to boiler ignition lockout.
It can result from a faulty gas valve, low gas pressure or too much gas, damaged wired connections, or faulty ignition leads and flame sensor probes.
To fix it, you’ll need to call a Gas Safety registered heating engineer to test the electrode and ignition lead and replace them if necessary.
Are you considering a new boiler and wondering what size you need? Or are you wondering which boiler installation company is best?
#6 Faulty Boiler Fan
The fan in your boiler plays an important function.
It creates a draught that pushes out the harmful emissions and gases that the boiler produces into the boiler flue, which carries them outside your home and disperses them into the atmosphere.
If the boiler’s CPB determines the fan isn’t operational or is faulty, it can initiate a boiler ignition lockout since it would be dangerous to let the boiler continue running.
You can easily notice whether the fan has malfunctioned because it normally makes a slight noise when in operation.
If you can’t hear any sound, a faulty fan may be causing the boiler ignition lockout. You’ll need to call a specialised heating engineer to confirm the diagnosis and investigate fixing the fan.
Usually, a replacement fan is an expensive part to source. A new boiler may be a more cost-effective option, depending on the age and condition of the boiler.
What size boiler is right for your home? If you are considering a combi boiler, it is largely determined by the number of radiators in your home.
Check out our complete guide to new boiler installation here if you are wondering about the best type of boiler for your home.
How much may a new boiler cost? Are you considering converting from a conventional to a combi boiler? Use our boiler installation cost calculator to get an estimation.
#7 No Pilot Light
The pilot light should be lit inside a fully operational boiler.
However, if the internal electrode and ignition lead develop a fault and stop working, the pilot light can go out and not relight. Debris can also block the small jet of the pilot light.
The jet is usually very tiny, and even a small speck of dirt can block it and prevent the boiler from re-igniting.
The jet is cheap, and you can easily replace it. You can also remove, clean, and reinstall it to fix the issue.
#8 Fuel Issues
Your boiler needs fuel to operate.
A boiler ignition lockout may occur if there’s little to no fuel, like gas or oil.
Check whether there is a gas outage or if other gas appliances have a supply. You can also check with neighbours to see if there is a local issue or look at your regional supplier’s website.
Low or high gas pressure and freezing of the gas regulator in cold weather can also lead to a failed ignition.
#9 Human Error Issues
Human error can occur when you forget some simple settings or obligations that can cause a boiler ignition lockout. These include:
- Thermostat settings – The thermostat controls the temperature the boiler will activate upon (if programmed to be running) and how much it will heat the property. The boiler may fail to start if the thermostat is set too low.
- Timer clock and programme – As briefly mentioned above, a boiler often has a programme that controls when the boiler should operate. If the boiler clock or the programme is incorrect, the boiler will not turn on.
- Prepayment meter – If the boiler has a prepayment meter associated with it, you should check to ensure it has a credit balance applied to enable the heating system to work.
How to Fix a Boiler Ignition Lockout Next Steps
This guide covers a wide range of boiler ignition lockout issues. If the basic troubleshooting hints included do not resolve the ignition problem you are facing, always seek the advice of a qualified heating engineer for further support.
The cost to fix the boiler will vary depending on the cause of the ignition issue. Some causes may require labour only to clear blockages, while others require expensive replacement parts. If the costs are too high, discuss replacing the boiler with your heating engineer.
Sources and References
- energysavingtrust.org.uk/is-now-a-good-time-to-get-a-heat-pump/