A boiler reset can sometimes clear a temporary fault or lockout. However, resetting does not repair the cause of a recurring problem.
What Does Resetting Do?
Modern boilers monitor their own operation.
If the boiler detects certain problems, it may stop working and display:
- a fault code
- a warning light
- a lockout message
- a reset symbol
Resetting tells the boiler to try starting again.
Sometimes that is all that is needed.
However, if the fault remains, the boiler may lock out again.
So:
Reset = try restarting
Reset ≠ repair the fault
Check the Fault Code First
Before pressing Reset, look at the boiler display.
If you can see a fault code, write it down or take a photo.
Then, check the user instructions for your exact boiler model.
The code may help explain why the boiler has stopped.
This is useful if you later need an engineer too.
Check the Simple Things
Before resetting, check the normal user controls.
Ask:
- Does the boiler have power?
- Is the heating switched on?
- Is the thermostat asking for heat?
- Is the timer or programmer set correctly?
- Is there a fault code?
- Is the system pressure within the range specified for your boiler?
- If you use gas, is there an obvious wider supply problem?
A boiler cannot solve a problem caused by another control simply because you press Reset.
Check Boiler Pressure
If you have a sealed heating system, check the pressure display or gauge.
Very low pressure can cause some boilers to stop operating.
Do not assume every boiler needs exactly the same pressure.
Instead, check the instructions for your model.
If the system needs repressurising, follow the manufacturer’s user instructions.
If the pressure keeps falling, don’t keep topping it up and resetting the boiler.
The cause needs investigating.
Learn more: Boiler Pressure and Radiators →
How Do You Reset a Boiler?
The exact method depends on the boiler.
Some have a dedicated Reset button.
Others may require you to:
- press and hold a button
- turn a control to a reset position
- select Reset on a display
So, use the instructions for your exact make and model.
Do not rely on instructions for a different boiler that merely looks similar.
How Long Should You Press Reset?
Again, this depends on the boiler.
Some reset immediately. Others require a button to be held for several seconds.
Follow the manufacturer’s instructions.
Holding buttons for longer or repeatedly pressing them will not make a genuine fault disappear.
What Happens Next?
After a reset, the boiler may run through its normal starting sequence.
If there is demand for heating or hot water, it may then start operating.
Give it time to complete that process.
If it returns to normal, continue to keep an eye on it.
If the same fault quickly returns, resetting it again and again is not the answer.
Don’t Keep Resetting It
A boiler that repeatedly locks out is telling you that something needs attention.
For example:
One temporary lockout → reset may solve it
Same fault keeps returning → investigate the cause
Repeatedly resetting a boiler can hide an ongoing problem without fixing it.
So, if the fault returns, use the fault code and manufacturer guidance to decide what to do next.
What If There Is No Heating?
If the boiler appears to be working but the radiators remain cold, check the heating controls before assuming the boiler needs resetting.
Check:
- room thermostat
- heating timer
- radiator valves
- boiler pressure
If only one radiator is cold, the problem is unlikely to be solved by resetting the boiler.
Learn more: Boiler Pressure and Radiators →
What If There Is No Hot Water?
First, identify what type of hot-water system you have.
If you have a combi boiler, the boiler normally produces hot water when you open a hot tap.
If you have a cylinder, your hot water may depend on a timer, boiler, immersion heater or another heat source.
So, a Reset button is not always the right place to start.
Learn more: Your Hot Water System →
What If the Boiler Has No Power?
If the display is completely blank, pressing Reset will not help.
Check the normal user-accessible electrical controls, such as whether the boiler appears to have been switched off.
If an electrical protective device has operated, do not repeatedly reset it if it trips again.
Repeated tripping can indicate a fault that needs investigation.
Do not remove boiler covers or attempt electrical repairs yourself.
What If the Boiler Keeps Losing Pressure?
Resetting will not repair pressure loss.
If the pressure repeatedly falls, possible causes can include a leak or another problem within the heating system.
Look for obvious signs of water around radiators, valves, visible pipes and the boiler area.
Then, if the pressure continues to fall, get the cause investigated.
Learn more: Boiler Pressure and Radiators →
What If the Boiler Makes Unusual Noises?
Some boiler and heating-system noises are normal.
However, if the boiler suddenly starts making severe or unusual noises, don’t repeatedly reset it to see whether they disappear.
Switching a fault away on the display does not necessarily remove its cause.
If you are concerned, get suitable professional advice.
Never Remove the Boiler Cover
A reset is a user control.
Opening or dismantling the boiler is not.
Do not remove the boiler casing or interfere with:
- gas components
- combustion parts
- safety devices
- internal wiring
- internal valves
Work on gas appliances must be carried out by someone appropriately qualified where required.
If You Smell Gas
Do not try to solve a suspected gas leak by resetting the boiler.
Avoid flames and anything that could create an ignition source.
Follow the official gas-emergency instructions for your area and contact the appropriate emergency service.
A boiler Reset button is not a gas-safety control.
If You Suspect Carbon Monoxide
Carbon monoxide cannot be seen or smelled.
If a carbon monoxide alarm sounds, or you suspect a carbon monoxide problem, do not keep using or resetting the boiler.
Follow the alarm and emergency guidance and get the situation checked appropriately.
When Should You Call an Engineer?
Get suitable professional help if:
- the same fault keeps returning
- the boiler repeatedly locks out
- pressure repeatedly falls or rises too high
- there is a leak
- the boiler will not reset
- an electrical protective device repeatedly trips
- the boiler makes concerning noises
- the manufacturer’s instructions tell you to seek help
- you are unsure whether it is safe to continue
For work on a gas boiler, use a suitably qualified Gas Safe registered engineer.
A Simple Reset Checklist
Before Reset:
- Read the fault code.
- Check the boiler instructions.
- Check power and normal controls.
- Check pressure if applicable.
- Look for anything obviously wrong.
Then:
- Reset exactly as the manufacturer instructs.
- Allow the boiler to restart.
- See whether the fault returns.
If it does:
Stop repeatedly resetting and investigate the cause.
Key Points
A boiler reset can clear some temporary faults.
However, it does not repair an underlying problem.
Always check the fault code before resetting.
Then, use the instructions for your exact boiler model.
Don’t remove covers or interfere with internal components.
Most importantly:
If the same fault keeps returning, stop resetting and find out why.
Important Information
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