How to Reset a Baxi Boiler
5 October 2026
How to Reset a Baxi Boiler
To reset a Baxi boiler, identify which control system your model uses. If it has a dedicated reset button, press it until the lockout light goes out. If it has an on, off and reset selector, turn the selector to the R position, hold it there for at least five seconds and release it. Older models with a thermostat control knob may reset when the knob is turned fully anticlockwise and held until the red lockout light goes out.
Quick answer: Record the fault code, check that the boiler has power and confirm the system pressure is within the range stated in your manual. Press the dedicated reset button or hold the selector at R for at least five seconds, depending on the model. Release the control and wait for the display to return to its normal temperature reading. If the boiler locks out again, stop resetting it and arrange an engineer’s inspection.
A reset clears a temporary lockout and asks the boiler to start its normal ignition sequence again. It does not repair a leaking component, restore lost pressure, clear a blocked condensate pipe or correct an ignition fault.
Baxi has produced many boiler ranges with different control panels. The reset method for a Baxi 600, 800, Duo-tec, Platinum, EcoBlue or an older model may differ. Check the model name and user manual before operating unfamiliar controls.
When Should You Reset a Baxi Boiler?
A reset may be appropriate when:
The boiler displays a lockout fault
A red lockout or flame-failure light is illuminated
The boiler has stopped after a temporary interruption
The pressure has been restored after a low-pressure lockout
A frozen condensate pipe has been thawed safely
The user manual specifically tells you to reset the boiler
Do not reset the boiler simply because the heating is not on. First check the thermostat, programmer and heating schedule. The boiler may be operating normally but not receiving a request for heat.
Identify Your Baxi Boiler and Reset Control
The model name may be printed on the front, underneath the boiler or on a label inside the drop-down control panel. Do not remove the main boiler casing to find it.
If the model name is unclear, look for the serial-number label or the Benchmark service record. Baxi’s online user-guide library can then be used to find the instructions for that exact boiler.
Baxi boilers normally use one of three reset-control arrangements:
Control type | How to recognise it | General reset method |
|---|---|---|
Dedicated reset button | A button marked Reset or with a reset symbol | Press until the red lockout light goes out |
On, off and selector switch | A rotary control with an R position | Turn to R, hold for at least five seconds and release |
Thermostat control knob | An older rotary temperature control with a lockout light | Turn fully anticlockwise until the red light goes out, then return to the required setting |
These are general Baxi methods. Always use the method stated in the manual for the exact model.
What to Check Before Resetting the Boiler
1. Record the Error Code
Write down the complete code before pressing reset. Take a photograph of the display if necessary. Once the boiler restarts, the fault code may disappear, making a recurring problem harder to describe to an engineer.
Some newer boilers show a letter, dots and numbers. Record the entire sequence rather than only the final digits.
2. Check the System Pressure
Look at the pressure gauge or digital pressure reading while the heating system is cold. Many sealed Baxi systems normally operate at approximately 1 to 1.5 bar when cold, but the correct range must be confirmed in the boiler’s manual.
If the pressure is too low, resetting will not correct the underlying problem. The boiler may immediately return to lockout. Repressurise it only when you understand the filling system and the manufacturer permits this as a user task.
The InstantCost guide on how to increase boiler pressure explains how to recognise a low-pressure fault and when recurring pressure loss needs professional investigation.
3. Check the Power Supply
Confirm that the boiler’s fused spur is switched on and that the display has power. Check whether a circuit breaker has tripped, but do not repeatedly reset a breaker that trips again.
If there has been a power cut, allow the boiler controls to restart before pressing reset.
4. Check the Heating Controls
Increase the room thermostat above the current room temperature and make sure the programmer is requesting heating. If the boiler provides hot water normally but the radiators remain cold, the problem may involve the controls rather than a boiler lockout.
5. Check for an Obvious Water Leak
Look around the boiler, visible pipes and radiators without removing any covers. Do not reset or repressurise a boiler when water is leaking from the appliance or an electrical component.
6. Consider a Frozen Condensate Pipe
During freezing weather, an external condensate pipe may freeze and cause the boiler to lock out. Some Baxi models may show E133, E28 or another model-specific code.
A frozen section can sometimes be thawed with a hot-water bottle, warm cloth or warm water. Do not pour boiling water onto the plastic pipe. Water spilled outside can refreeze and create a slipping hazard.
How to Reset a Baxi Boiler With a Reset Button
Use this method only when the boiler has a clearly identified reset button.
Record the displayed fault code or lockout-light pattern.
Check that the boiler pressure is within the range stated in the manual.
Confirm that there is no smell of gas, visible leak or electrical danger.
Locate the dedicated reset button on the control panel.
Press the button until the red lockout light goes out or the display changes.
Release the button.
Wait while the boiler completes its starting sequence.
Check whether the burner symbol appears and whether the flow temperature begins to rise.
The boiler may take a short time to start, especially when the heating controls are not currently calling for heat. Do not keep pressing the reset button while it is completing its checks.
How to Reset a Baxi Boiler With a Selector Switch
Some Baxi boilers have a rotary selector with positions for off, heating, hot water and reset.
Open the drop-down control panel if the selector is behind it.
Record the fault code or neon-light pattern.
Turn the selector to the R or Reset position.
Hold it in that position for at least five seconds.
Release the selector so it returns to its normal operating position.
Wait for the fault code to be replaced by the boiler’s normal display.
Request heating or hot water and check whether the burner starts.
Do not force the selector beyond its marked positions. A loose, jammed or broken control needs professional attention.
How to Reset an Older Baxi With a Thermostat Knob
Certain older Baxi boilers use the main temperature-control knob for resetting.
Confirm that the red lockout light is illuminated or flashing.
Turn the boiler thermostat control fully anticlockwise.
Hold it in that position until the red lockout light goes out.
Turn the knob back to the required operating temperature.
Check whether the burner light comes on when the timer or thermostat requests heat.
Do not repeatedly rotate the control if the lockout light remains on. Confirm the model instructions and arrange an engineer if the boiler does not respond.
Compare Boiler Repair and Replacement Costs
Use InstantCost’s current UK heating figures to plan for professional diagnosis, servicing or boiler replacement.
What Happens After the Baxi Boiler Is Reset?
When the reset is successful, the lockout light or error code should clear. The boiler may display its current flow temperature and begin its normal ignition sequence.
If the heating controls are calling for heat, you may notice:
The pump beginning to run
The burner or flame symbol appearing
The displayed temperature starting to rise
Radiator pipes gradually warming
Hot water returning on a combi boiler
Give the system time to respond. Radiators do not become hot immediately after the burner starts.
Monitor the boiler over the next few hours. Record any code that returns and how long the boiler operated before locking out again.
Why Will My Baxi Boiler Not Reset?
The Pressure Is Too Low
A reset cannot restore water pressure. If the gauge is below the model’s operating range, the boiler may remain locked out until the system is correctly repressurised.
If pressure falls again shortly after topping up, there may be a leak, faulty expansion vessel or pressure-relief problem. Repeatedly adding water can introduce oxygen and increase corrosion inside the heating system.
The Ignition Fault Is Still Present
The boiler will lock out again if it cannot establish or maintain a safe flame. The cause could involve the gas supply, ignition components, gas valve, flame detection or condensate system.
These are not user repairs. Do not remove the casing or attempt to reach the burner.
The Condensate Pipe Is Still Blocked
Resetting before a frozen or blocked condensate pipe is cleared may cause the same fault to return immediately. Check only the accessible external section and follow the manufacturer’s method.
The Boiler Is Overheating
An overheating lockout can result from poor circulation, a pump problem, a closed valve, air, sludge or a faulty sensor. Allow the boiler to cool, but do not repeatedly reset it if the code returns.
A Sensor or Internal Component Has Failed
Temperature sensors, fans, pumps, valves and control boards can produce faults that a reset cannot repair. Record the code and arrange a Gas Safe registered engineer.
The Reset Control Is Not Being Held Long Enough
On Baxi models with an R selector position, Baxi instructs users to hold the control there for at least five seconds. Briefly turning the dial to R may not complete the reset.
Common Baxi Fault Codes Seen Before a Reset
Baxi fault codes vary by model. Always check the user guide for the exact boiler before taking action.
Example code | Possible meaning on relevant Baxi models | User action |
|---|---|---|
E119 | Low system pressure | Check the gauge and manual before repressurising |
A.02.06 | Low heating-circuit pressure on certain newer models | Check pressure and follow the exact model guide |
E133 | Ignition, flame, gas-supply or condensate-related lockout | Check for a frozen condensate pipe in freezing weather, then seek help if the code returns |
E20 | Central-heating temperature-sensor fault on relevant models | Arrange an engineer if it persists |
H.03.02 | Temporary flame loss on certain newer models | Follow the manual and obtain help if repeated |
The same number can have different relevance across product generations. Do not buy parts or attempt an internal repair based only on a code found online.
How Many Times Should You Reset a Baxi Boiler?
Try one reset after completing the safe checks described in the boiler manual. If it does not restart, check the displayed code and instructions once more.
Do not keep resetting a boiler that repeatedly locks out. A safety control has stopped the appliance because it detected a problem. Repeated attempts may hide a developing fault without correcting it.
Arrange professional help when:
The same fault returns after one reset
The boiler repeatedly loses pressure
Water is leaking from the boiler or discharge pipe
The electrical supply keeps tripping
The boiler makes banging, grinding or unusual ignition noises
A burning smell is present
There is no heating or hot water after the reset
The manual states that the code requires an engineer
Resetting a Baxi Boiler After Repressurising
When low pressure caused the lockout, restore the pressure before resetting the boiler. Use the filling method specified for the installation and stop at the cold pressure stated in the manual.
Close every filling-loop valve completely. Then use the correct reset button, selector or control-knob method.
Monitor the gauge after the heating has run. A modest rise as the water warms is normal. A large increase, discharge of water or a rapid fall after cooling indicates a fault that needs investigation.
Resetting a Baxi Boiler After a Power Cut
Most boilers restart automatically when power returns, provided the controls still request heating and no fault is present.
If the display remains blank, check the fused spur and household circuit breaker. Do not replace a fuse with one of a different rating. If a new fuse fails or the circuit trips again, stop and arrange electrical or heating assistance.
If the display returns with a lockout code, record it and perform the model’s normal reset once.
Resetting After Thawing a Frozen Condensate Pipe
Switch the boiler off before treating the frozen pipe. Warm the accessible frozen section gradually with a hot-water bottle, reusable heat pack, warm cloth or warm water.
Never use a naked flame, heat gun or boiling water. Once the blockage has thawed, dry the area, restore the boiler’s power and follow the correct reset procedure.
If the boiler remains locked out or the pipe repeatedly freezes, ask an engineer to assess the condensate route, insulation and pipe size.
How Much Does a Baxi Boiler Repair Cost?
Resetting the boiler yourself costs nothing. If the fault returns, the following InstantCost 2026 UK heating figures provide a guide to professional costs:
Heating work | Typical UK cost |
|---|---|
Standard boiler service | £70 to £120 |
Heating engineer call-out and diagnosis | £80 to £150 |
General fault diagnosis and repair | £90 to £280 |
Pressure-relief valve replacement | £100 to £200 |
Expansion-vessel recharge or replacement | £150 to £300 |
New combi boiler supplied and fitted | £1,900 to £3,200 |
The final repair price depends on the fault, model, part availability, location and warranty status. Confirm whether diagnosis, labour, parts and VAT are included in the quote.
Baxi Boiler Reset Safety
Resetting the appliance from its user controls is different from repairing it. Never remove the sealed boiler casing or adjust internal gas, combustion or safety components.
If you smell gas:
Do not reset or operate the boiler
Do not use electrical switches, plugs or naked flames
Open doors and windows
Turn off the gas at the emergency control valve if it is safe
Leave the property and call the National Gas Emergency Service on 0800 111 999 in Great Britain
In Northern Ireland, call the gas emergency service on 0800 002 001
If a carbon-monoxide alarm sounds or anyone develops a headache, dizziness, nausea, confusion or unusual tiredness, leave the property and seek urgent assistance.
Baxi’s official guide to resetting a Baxi boiler confirms the reset methods for dedicated buttons, thermostat knobs and selector switches. Use the specific product manual where its instructions differ.
Only a Gas Safe registered engineer may legally work on the gas components of a boiler in the UK. Check that the engineer is qualified for boilers, as registration can cover different categories of gas work.
Common Baxi Boiler Reset Mistakes
Resetting Without Recording the Code
The code may disappear after a successful reset. Record it first so an engineer can investigate a recurring fault.
Resetting Before Correcting Low Pressure
A reset cannot add water to the heating circuit. Correct the pressure first only when the manual permits it and you understand the filling system.
Briefly Turning the Selector to R
Many selector-controlled Baxi boilers require the switch to remain at R for at least five seconds. Turning it quickly may not trigger the reset.
Repeatedly Resetting a Lockout
A recurring lockout indicates an unresolved fault. Stop after the problem returns and arrange an engineer.
Using Boiling Water on a Frozen Pipe
Boiling water can damage plastic condensate pipework and create a freezing hazard on the ground. Use warm water or gentle heat.
Removing the Boiler Casing
The casing forms part of the gas appliance and should only be removed by a suitably qualified engineer.
Frequently Asked Questions
Where is the reset button on a Baxi boiler?
It depends on the model. Some have a dedicated button on the fascia. Others use an R position on the main selector or the boiler thermostat knob. Check the model’s user manual before operating the controls.
How long should I hold the Baxi reset control?
For a Baxi model with an on, off and reset selector, hold it at R for at least five seconds. A model with a dedicated button or thermostat knob may use a different method.
Why does my Baxi boiler keep showing a red light?
A constant or flashing red lockout light means the boiler has detected a fault. Try the model’s approved reset once after completing the basic checks. Arrange an engineer if the light or fault returns.
Will resetting a Baxi boiler fix low pressure?
No. The system must first be returned to the pressure stated in the boiler manual. If the pressure repeatedly falls, the heating system needs to be checked for a leak or component fault.
What does Baxi error code E133 mean?
On relevant Baxi models, E133 can relate to ignition, flame, gas-supply or condensate problems. A frozen condensate pipe is one possible cause during cold weather. Seek professional help if the code returns after one appropriate reset.
Should I turn off the electricity before resetting a Baxi boiler?
Not for the normal control-panel reset unless the manual instructs you to do so. If you are thawing a frozen condensate pipe, Baxi advises switching the boiler off first. Never operate electrical controls if there is a gas smell or water is affecting the appliance.
Is Your Baxi Boiler Still Locking Out?
Compare current boiler service, repair and replacement costs before arranging professional help.