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Quick answer
Most modern boilers have a reset button or a reset option on the display. Press it once, wait for the boiler to run through its start-up sequence, and see whether it fires. If it locks out again, check the simple things (gas supply, pressure, frozen condensate pipe) before trying once more. If the boiler still locks out after two or three attempts, stop: repeated resets can mask a real fault and some manufacturers limit how many are allowed before a hard lockout. At that point a Gas Safe registered engineer needs to look at it.
Key takeaways
- A reset clears a lockout; it does not fix the cause of the lockout.
- Check gas supply, water pressure and the condensate pipe before pressing reset again.
- Two or three attempts is a sensible limit. Beyond that you risk masking a fault.
- Never open the boiler casing. Only a Gas Safe engineer should work inside a gas appliance.
- If you smell gas, do not reset anything. Turn off the gas at the meter and call the National Gas Emergency number on 0800 111 999.
What a lockout actually is
A lockout is the boiler protecting itself. If it tries to light and cannot detect a flame, if it overheats, if water pressure is too low or if a sensor gives an unexpected reading, the control board stops the boiler and shows a fault code. The boiler will not try again until someone resets it. This is a safety feature, not a malfunction in itself.
How to reset your boiler
- Note the fault code. Write it down before you do anything. It tells an engineer far more than “it stopped working”. Our guide to boiler display icons and symbols can help you read it.
- Find the reset control. It is usually a button marked with a flame, a circular arrow or the word “reset”. On some models it is a menu option.
- Press and hold for the time stated in the manual, usually a few seconds.
- Wait. The boiler will run its fan, then attempt ignition. This can take a minute.
- Check the result. If the burner lights and the display returns to normal, run the heating and hot water for a few minutes to be sure.
Check these before a second attempt
Gas supply. Is the hob working? If you have a prepayment meter, is there credit? Our post on prepayment meters and boilers not working covers the common traps.
Water pressure. Most sealed systems should sit around 1 to 1.5 bar when cold. If it is below 1 bar, see how to repressurise a combi boiler.
Frozen condensate pipe. In cold weather, a frozen condensate pipe is one of the most common causes of a lockout. See frozen condensate pipe: how to thaw it.
Power. A tripped fused spur or a recent power cut can leave the boiler confused. Switch it off at the spur for a minute and back on.
When to stop trying
Stop resetting and call an engineer if:
- The boiler locks out again straight away, or after a short run.
- You have reset it more than two or three times in a day.
- You hear banging, see water leaking or smell burning.
- The same fault code keeps returning over several days.
Repeated resets can hide a developing problem such as a failing ignition electrode, a blocked flue or a faulty gas valve. Some boilers also limit resets and will enter a harder lockout that needs an engineer to clear.
What never to do
Do not remove the casing, bypass sensors or try to adjust the gas valve. Working on the inside of a gas appliance without Gas Safe registration is unsafe and, if done for payment, illegal. If you smell gas at any point, turn off the supply at the emergency control valve by the meter, open windows and call 0800 111 999. Our guide to the emergency gas shut-off valve shows where to find it.
Book with Gasmaster
Boiler still locking out after a reset? Gasmaster Plumbing & Heating, Gas Safe registered (220932), carries out boiler repairs across Stoke-on-Trent, Newcastle-under-Lyme and Biddulph. Get in touch or book through our boiler service booking page.
Frequently asked questions
Is it safe to reset my boiler?
Yes, using the reset button is designed to be safe for householders. The risk comes from repeatedly resetting without finding out why it keeps locking out.
Why does my boiler keep needing a reset?
A recurring lockout usually points to an ignition, pressure, condensate or flue issue. Our article on a boiler that keeps turning off goes through the common causes.
Will resetting my boiler lose my settings?
Normally no. A reset clears the lockout, not your programmed times or temperatures. Switching power off for a long time can reset the clock on some models.
How long after a reset should the boiler fire?
Usually within a minute or so. If nothing happens after a couple of minutes, check the display for a new code.
Sources
- Gas Safe Register, safety advice for householders (gassaferegister.co.uk)
- Health and Safety Executive, Gas Safety (Installation and Use) Regulations 1998 (hse.gov.uk)
- National Gas Emergency Service, 0800 111 999
Related services
Abdul runs Gasmaster Plumbing & Heating and has worked on boilers, heating and gas appliances across Stoke-on-Trent since 2005. He is Gas Safe registered (reg. 220932), and these articles come from his day to day work in homes and businesses across Staffordshire, Cheshire and Derbyshire.
