If your boiler has suddenly switched off or is displaying an error code, don’t panic; this usually means it has entered “lockout” mode. Lockout mode is a built-in safety feature that prevents the boiler from operating when an issue is detected. Common triggers include low pressure, ignition failure, a power interruption, or overheating.
Once the underlying issue is resolved, the fastest way to restore your heating and hot water is to reset the boiler. A reset clears the fault and gives the boiler a clean start; most homeowners can perform the basic checks needed before pressing that button.
Issues You Can Fix As A Homeowner
Resetting a boiler without checking a few essentials first can lead to repeated faults or mask a more serious issue. However, before calling in a professional to fix the error, here are a few simple checks to perform.
Make Sure The Gas Is Reaching the Boiler
If the error mentions ignition failure, no flame, or a detected flame that has been lost, start by confirming that your gas supply is working. Try lighting another gas appliance, such as your hob or oven.
- No flame anywhere? The issue isn’t your boiler, it’s the gas supply.
- Appliances working? It’s time to proceed to the next step.
Before you go running off to tackle the next task, make sure also to check that your prepayment meter hasn’t run out of credit, as well as if the external gas valve (often located outside the property) hasn’t been turned off.
Check The Boiler Pressure
Boiler pressure isn’t just a random number on the gauge. It’s one of the most crucial factors in ensuring your heating system operates safely and efficiently. If the pressure is too low or too high, the boiler can’t circulate water properly through your radiators and internal components. When that happens, the boiler locks out to prevent damage.
Your boiler runs most efficiently at 1.0–1.5 bar when cold, and most models have a green zone on the pressure gauge to indicate the ideal range.
Low Pressure (Below 1.0 bar)
If the pressure is below 1.0 bar, your boiler won’t have enough water in the system to create the flow it needs to heat your home. This causes ignition failure, lukewarm radiators, and forces the boiler to engage its lockout mode.
To increase your boiler’s pressure, or repressurise it, you will need to use the filling loop (the silver flexible hose underneath the boiler) to slowly add water until the needle rises into the green zone. You’ll usually hear the system filling as you turn the valves.
High Pressure (Above 2.0 bar)
If the pressure exceeds 2.0 bar, it is too high and will eventually put strain on internal seals, valves, and pipes. Left unchecked, this can cause leaks or trigger yet another lockout as a safety measure.
To bring down the boiler’s pressure, you will need to bleed a radiator using a radiator key gently. This releases a small amount of water and air, helping the pressure drop back into the safe operating range. Once your pressure sits comfortably between 1.0 and 1.5 bar, the boiler has the correct amount of water to circulate heat properly.
Check The Boiler’s Power Supply
It sounds obvious, but it’s easy to overlook. Most boilers are connected to a fused spur switch, which resembles a single large switch located near the boiler, similar to a light switch.
Make sure it’s turned on. However, if your display is still blank, check your fuse box for any tripped circuits. If a switch has flipped down, that’s likely the cause. Flip it back up to restore power and see if the boiler display comes back on.
Only Reset Once Everything Checks Out
Once you’ve confirmed your gas supply, boiler pressure, and power are all in order, you can safely press the reset button. Skipping these steps could land you back on the same error screen, or worse, hide a fault that needs professional attention.
Time To Reset Your Boiler
As you’d assume, every boiler manufacturer has its own process for resetting the boiler. Additionally, even between brand models, these reset functions will be different.
Worcester Bosch Boilers
Most Worcester Bosch boilers, especially the Greenstar range, have a clearly marked reset button on the front of the unit. This reset button is small with a flame icon and a circular arrow around it.
- To use this reset button, press and hold it for 3–5 seconds.
- Release the button and wait. You’ll hear the boiler go quiet for a moment as it runs a safety check.
- The boiler should then attempt to ignite.
Digital Display Models: There is also the reset method, which involves a digital display and is more common with newer models. These models often display fault codes such as EA, A1, C6, or E9.
- To reset using the display, open the boiler’s control panel flap (if your model has one).
- Use the arrow or menu buttons to navigate to “Reset”. Select Reset and confirm.
- Wait for the boiler to restart.
- After the reset, the screen should return to the standard temperature display.
Vaillant Boilers
Vaillant ecoTEC boilers make resetting simple, whether you’re using an older push-button model or a newer touchscreen version.
Physical Button: Most ecoTEC models have a reset button marked with a flame icon and a cross, or a circular arrow.
- To reset, press and hold the button for 3 seconds. Release it and wait while the boiler restarts.
- The fault code should clear, and the boiler will attempt to ignite.
Digital Reset: Newer ecoTEC Plus models might use a digital reset option.
- To reset these newer models, use the menu to scroll to the “Reset” option. Select and confirm the reset.
- Once it has run a short safety check, it will then relight itself.
Ideal Boilers
Ideal boilers such as the Logic, Vogue, and Atlantic ranges all follow a similar reset process. Typically, a reset button is located on the right-hand side of the control panel, often marked “RESET” or depicted with a circular arrow.
There can be a fault code that appears to help diagnose the issue.
- To reset, press and hold the reset button for 3 to 5 seconds.
- Release once the boiler display begins flashing or changing.
- Wait for the boiler to attempt ignition. If successful, the fault light will turn off.
Baxi Boilers
Baxi combis such as the 600, 800, Duo-Tec, and Platinum use a simple reset button. Often, there is a simple “R” button. You’ll find it near the display or next to the temperature dials.
- Press and hold the R button for 2 to 5 seconds. Release and wait for the boiler to restart.
- You’ll hear the fan, then the ignition sequence.
Alpha Boilers
Alpha models typically feature a dedicated reset button located on the front or beneath the flip-down panel.
- To reset, press and hold for 3 to 5 seconds. Release and wait for the boiler to cycle.
- If your Alpha boiler has a digital display, open the menu and navigate to the “Reset” option. Select and confirm.
After allowing the boiler to power down and back up again, wait for the system to complete its safety checks before heating resumes.
Glow-worm Boilers
Glow-worm boilers (Betacom, Energy, Flexicom) keep the reset straightforward. Typically, Glow-worm boilers often hide the reset button behind the front cover or under the control flap. Look for a button marked with a “Reset” label or circular arrow icon.
- Press and hold the button for 3 to 5 seconds.
- Release and allow the boiler to restart.
Potterton Boilers
Potterton boilers, such as their Promax or Titanium models, usually have a small reset button marked with “R” or a circular arrow on the front control panel. For older models, you’ll often find it near the temperature control dial or just below the LCD display.
Press and hold the button for 5 seconds until the fault code clears or the boiler restarts.
Ariston Boilers
Ariston boilers commonly reset through the digital display.
- To perform a digital reset, press the OK or Reset button on the control panel. Hold for a few seconds. The fault code should disappear.
- If your Ariston boiler has a physical reset button, such as the one found on the Genus range, press and hold it for 2 to 5 seconds.
Navien Boilers
Navien boilers (NCB, NPE series) reset through the digital interface. The steps of using this digital reset process involve:
- Press the Mode button until “Reset” appears on the screen.
- Press OK to confirm.
- The display will show the reset in progress.
- Once complete, the boiler will attempt ignition.
Main Heating Boilers
Main Heating boilers (under the Baxi brand) are designed with a very straightforward reset process. You’ll usually find the reset control on the front of the boiler, clearly marked as “Reset” or featuring a flame symbol crossed out.
- Press the reset button.
- Hold it for 3–5 seconds.
- Release once the red fault light goes out or the display returns to normal.
If the light immediately returns or the boiler won’t relight, you’ll need to check the pressure or gas supply before attempting another reset.
ATAG Boilers
ATAG boilers, including popular models such as the iC and Economiser Plus, typically feature a physical reset button located on the main control panel. This button is usually marked with a curved arrow or the word “Reset.”
- Press the reset button.
- Keep it held for 5–10 seconds until the display flickers or the boiler begins its start-up cycle.
- Wait for the boiler to run through its safety checks. Once done, it should attempt ignition.
Some of the latest ATAG models don’t have a physical reset button. If yours uses a digital menu:
- Open the Menu.
- Scroll to Reset.
- Select and confirm the option.
- The boiler will restart automatically and return to its standard temperature display if the reset was successful.
Intergas Boilers
Most Intergas models, including the ECO RF, Rapid, and HRE, place the reset button directly on the front control panel. It may appear as a small round button or be labelled “Reset.”
- Press and hold the reset button for about 5 seconds.
- The fault code should clear from the screen.
- You’ll usually hear the fan spin up and the ignition click as the boiler attempts to relight.
If you have a newer Intergas Xtreme with a digital interface, the reset is handled through the screen:
- Use the control dial or buttons to open the menu.
- Navigate to the Reset option.
- Confirm the selection.
- The boiler will then restart and run a short safety cycle.
Viessmann Boilers
Viessmann boilers, including the Vitodens 050-W, 100-W, and 200-W, use one of two reset systems depending on the model.
Button Reset (usually marked with a flame inside a circular arrow):
- Press the button.
- Hold it for 5 seconds until the display resets or the error code clears.
- The unit will power cycle and attempt ignition.
Digital Menu Reset:
- Press Menu or OK.
- Navigate to Reset.
- Confirm the reset.
- Allow the boiler a moment to run through its internal checks.
- If everything is resolved, it will restart and return to the standard temperature screen.
Vokera Boilers
Vokera boilers, from the Easi-Heat to the Mynute and Linea models, all follow a similar reset routine. Most units feature a reset button right on the front panel, usually marked with a curved arrow, a flame symbol, or simply the letter “R.”
- Press the reset button firmly.
- Hold it for 3–5 seconds until the red fault light switches off or the display resets.
- Release the button and give the boiler a moment to restart.
Some of the newer Vokera ranges don’t use a button at all. Instead, they include a selector dial with a dedicated Reset position.
- Turn the dial to Reset.
- Hold it there for a few seconds.
- Move the dial back to the Heating/Hot Water position.
- Your boiler should then run its ignition sequence automatically.
Keston Boilers
Keston boilers, particularly the C30 and System models, locate their reset control in a slightly more discreet location. The reset button is usually located on the right-hand side of the control panel, often hidden behind a small flip-down cover. It may show a circular arrow icon or the letter “R.”
- Open the small flap if your model has one.
- Press and hold the reset button for about 5 seconds.
- Release once the display flickers or restarts.
- The boiler should begin a fresh ignition cycle once the reset is accepted.
Ferroli Boilers
Ferroli boilers, such as the Modena, BlueHelix, and i25 series, make their reset function very accessible. On most units, the reset control is located on the front control panel, clearly labeled as “Reset” or identified by a flame-and-cross symbol.
- Press the reset button.
- Hold it for 2–5 seconds.
- Wait as the boiler shuts down briefly, performs its internal safety checks, and then attempts to relight.
- If everything is in good order, the fault code will clear and the boiler will return to normal operation.
What a Successful Reset Looks Like
If everything has gone to plan, a successful reset will mean:
- The error code should disappear.
- The display should return to the temperature screen.
- You should hear the fan start, followed by the ignition click.
- Radiators and hot water should begin heating normally.
However, an unsuccessful reset will mean:
- The same error keeps appearing.
- You hear banging or whistling noises.
- The boiler overheats or shuts down immediately after starting.
- You’re unsure what the fault code means.
Resetting your boiler repeatedly won’t solve a deeper issue. It’s better to stop and get it checked if the problem persists. At this point, it’s best to stop, note down the error code, and contact a Gas Safe-registered engineer to investigate why the boiler keeps locking out.
Call WarmZilla For An Engineer
If your boiler still won’t fire up after a reset or keeps dropping back into lockout, it’s time to involve a Gas Safe registered engineer.
WarmZilla can connect you with reliable, fully vetted engineers who specialise in your specific boiler type. In most areas, we can have someone visit you within 48 hours, so you’re not left without heating or hot water for long.
When you reach out, ensure you have the fault code, your boiler’s brand and model, and a brief summary of the checks you’ve already performed. This helps the engineer diagnose the issue much faster.
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