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Last updated: 9th July, 2024


How to Reset Vaillant Boiler

How to Reset Vaillant Boiler

Key takeaways

  • Press and hold the reset button for three seconds to reset your Vaillant boiler.
  • Locate the button on the control panel, often marked with a flame icon.
  • Persistent faults should be resolved by a certified gas engineer.

The reset button on a Vaillant boiler typically has a small flame icon and can be found on the front display. Sometimes, it's not immediately visible, so check near the bottom of the panel. When you press and hold this button, you'll need to watch for changes on the display to confirm that the reset process is successful.

If THE Vaillant boiler has stopped working, you might be feeling frustrated and cold. Boilers can sometimes lock out due to faults, but the good news is that resetting them is usually straightforward. 

To reset Your Vaillant boiler, locate the reset button on the control panel, press it, and hold it down for three seconds. This can often clear minor faults and get your boiler up and running again.

The reset button on a Vaillant boiler typically has a small flame icon and can be found on the front display. Sometimes, it's not immediately visible, so check near the bottom of the panel. When you press and hold this button, you'll need to watch for changes on the display to confirm that the reset process is successful. If the boiler continues to show an error code, it might indicate a more serious issue that requires professional help.

It's important to remember that while a simple reset can solve many issues, persistent problems or recurring faults should be addressed by a certified gas engineer. Taking the time to carry out regular maintenance checks can also help prevent future boiler lockouts and ensure your heating system runs smoothly.

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Understanding Vaillant Boiler Error Codes

Vaillant boilers are equipped with systems that display error codes to help diagnose issues. Knowing how to interpret these codes can help in troubleshooting problems efficiently and possibly avoiding expensive repairs.

Common Error Codes and Their Meanings

Vaillant boilers display various error codes, each representing a specific issue. F75 is one of the most common, indicating a problem with the pump or pressure sensor. This often means the pump isn't detecting pressure changes, possibly due to a faulty pump or a blocked sensor.

Other frequent codes include F28, which signals an ignition failure, often due to a gas supply issue or faulty electrode. F29 indicates a flame loss, while F22 points to a dry fire or low water pressure. Understanding these codes helps in identifying whether a professional is needed or if a quick fix is possible.

Interpreting the Diagnostic Light Indicators

Vaillant boilers feature diagnostic lights and symbols on their control panels. These indicators help clarify the error codes further. A red light often signals a lockout, where the boiler has shut itself off to prevent damage.

A flashing light is generally less serious, showing a warning rather than a fault. For example, a yellow light might indicate a minor issue or the need for maintenance. The control panel may also show symbols like a flame with a line through it, indicating ignition problems, or a thermometer signifying temperature issues.

By carefully interpreting these lights and symbols alongside the error codes, homeowners can better understand the condition of their boilers and determine the next steps.

When to Call a Gas Engineer

Sometimes, resetting a Vaillant boiler isn't enough to fix the problem. In these cases, calling a Gas Safe registered engineer is necessary.

Signs You Need a Gas Engineer:

  • The reset button doesn't work.

  • The boiler keeps losing pressure.

  • There are unusual noises coming from the boiler.

  • You smell gas or suspect a gas leak.

Why Call a Gas Engineer?

  • Safety: Boilers can be dangerous if not handled properly. Only a trained professional should deal with potential gas and pressure issues.

  • Expertise: Engineers can accurately diagnose and repair faults, preventing further issues.

  • Legal Requirement: In the UK, only Gas Safe registered engineers are legally allowed to work on gas appliances.

How to Contact an Engineer:

  • Vaillant Service: You can book a service through Vaillant’s website or call their support line at 0330 100 3143.

  • Local Listings: Look for local Gas Safe engineers in your area through trusted directories or recommendations.

Regular servicing by a Gas Safe engineer can also help prevent future breakdowns. They will check the boiler’s efficiency and spot any early signs of trouble.

Preliminary Safety Checks Before Resetting

Checking safety measures before you reset the Vaillant boiler can prevent potential hazards and ensure the process runs smoothly. Focus on verifying the gas supply and valve operation and checking water pressure levels.

Ensuring Gas Supply and Gas Valve Operation

Before resetting the boiler, make sure the gas supply is continuous and the gas valve operates correctly. First, check the gas meter to confirm gas flow. If there's no gas, contact your provider.

Examine the gas valve next. It should be in the "on" position. If there’s any sign of damage or leakage, stop immediately and call a Gas Safe Registered Engineer. Also, inspect the boiler’s safety feature. This feature will shut off the gas supply if a problem is detected, so a malfunctioning safety feature may need an expert evaluation.

Verifying Water Pressure Levels

Water pressure in the boiler can affect its function and safety. Start by checking the Pressure Gauge on the boiler panel. Optimal pressure is usually between 1 and 1.5 bars.

Low Pressure may indicate a leak or need for a system refill. High Pressure can lead to system strain. Consult the Instruction Manual for your specific model’s ideal pressure range. If pressure levels are incorrect, refer to the manual's steps on adjusting it, or contact a Gas Safe Engineer to avoid damage.

Step-by-Step Guide to Resetting Your Vaillant Boiler

Resetting a Vaillant boiler can be necessary when you encounter simple issues such as low water pressure or minor error codes. Here are the clear steps to locate and safely use the reset button or dial.

Locating the Reset Button or Dial

The reset button on a Vaillant boiler is typically found on the front of the control panel. This button is usually near the bottom and marked with a small flame icon or a similar symbol.

To identify the reset button, consult your boiler manual for its exact location. If you no longer have the manual, look for a button that stands out amongst the other controls.

In some models, the button might be recessed or less prominent, making it less noticeable. Carefully examine the control panel and ensure you find the correct button to avoid unnecessary issues.

Follow Manufacturer's Resetting Procedure

Once the reset button is located, follow the manufacturer’s instructions to reset your Vaillant boiler correctly. Typically, you will need to press and hold the button for 3 seconds.

Do not press the reset button repeatedly, as this can harm the control panel and lead to costly repairs.

After holding the button, watch the display panel for any changes or messages. If the boiler resets successfully, the error code should disappear, and the boiler should start working again.

If the issue persists after resetting, or if you are unsure about any steps, it’s wise to consult the instruction manual or contact a Gas Safe Registered engineer for assistance.

Troubleshooting Post-Reset Issues

After resetting a Vaillant boiler, some users may encounter issues. This section covers common problems such as a boiler failing to reset and recurring error codes.

When a Boiler Fails to Reset

If the boiler fails to reset, users should first ensure they held the reset button correctly. The button usually needs to be pressed for about 3 seconds.

If the boiler still does not reset, check for any error codes displayed. These codes can pinpoint specific issues like a faulty gas valve or blocked pipes. Each error code corresponds to a different fault and requires different troubleshooting steps.

Safety should always come first. If there is any suspicion of a gas leak or another serious issue, contact a professional for repairs immediately. Attempting to fix complex boiler problems without proper expertise can be dangerous.

Dealing with Recurring Error Codes

Recurring error codes can indicate persistent problems. For example, a frozen pipe might cause repeated heating issues. Thawing the pipes can often resolve this problem. Check regularly to ensure the pipes remain unfrozen.

Another common issue involves a faulty gas valve. If the error code points to this problem, it might need professional repair or replacement. Users should not attempt to replace a gas valve themselves.

Finally, check the boiler’s pressure. Low pressure can lead to recurring error codes. Adjusting the pressure to the manufacturer's recommended level usually resolves this. If problems persist, a more in-depth inspection by a qualified technician may be required.

Keeping these steps in mind ensures that users can troubleshoot effectively and safely.

Maintenance Tips to Prevent Future Boiler Lockouts

Ensuring your Vaillant boiler runs smoothly involves regular servicing and maintaining the proper water pressure. These steps help in avoiding unexpected shutdowns and ensure efficient operation.

Regular Boiler Servicing by a Gas Safe Registered Engineer

An annual boiler service by a Gas Safe registered engineer is crucial. They will inspect, clean, and test the boiler. This service typically includes checking the burner, heat exchanger, and other vital components to ensure they are working correctly.

A heating engineer will also look for any signs of wear and tear or potential issues that could cause a lockout. Regular servicing not only helps in catching and fixing problems early but also ensures that the boiler runs efficiently, saving energy and costs.

Maintaining Optimal Water Pressure

Proper water pressure is essential for the boiler to function effectively. The pressure gauge on the boiler should show a reading between 1.0 and 1.5 bar. If the pressure is too high or too low, it can lead to system lockouts and other issues.

If the pressure drops too low, it can be topped up using the filling loop. On the other hand, if the pressure is too high, bleeding a radiator can help reduce it. Regularly checking and maintaining the correct water pressure can prevent many common boiler problems.

Upgrading to Modern Vaillant Boilers

Upgrading to a new Vaillant boiler offers numerous benefits, including enhanced efficiency and smart control features. These improvements can lead to a more reliable and cost-effective heating system.

Evaluating Benefits of New Vaillant Ecotec Models

New Vaillant EcoTec models provide better energy efficiency, leading to cost savings on utility bills. These boilers are designed with advanced technology that optimises fuel usage, ensuring that less energy is wasted.

Moreover, they offer improved performance with a more consistent and quicker heat supply. They also come with a modern control panel that simplifies operation and maintenance. This makes managing heating requirements straightforward and user-friendly.

In addition, Vaillant boilers are known for their reliability and durability. Investing in a new EcoTec model reduces the risk of breakdowns and expensive repairs, providing peace of mind for homeowners.

Considering Smart Control Features for Enhanced Efficiency

Vaillant boilers come equipped with smart control features that help to enhance efficiency. These features include programmable timers and Thermostats that allow homeowners to schedule heating times accurately.

Smart controls also include mobile app integration, which lets users adjust their heating settings remotely. This ensures that homes are heated only when needed, further cutting down on energy consumption.

Additionally, smart control systems can learn user preferences over time, automatically adjusting to the most efficient settings. This not only maximises comfort but also helps in achieving significant energy savings.

These integrated smart features make the new Vaillant EcoTec boilers a wise investment for those looking to upgrade their heating systems.

iHeat Boiler Service

At iHeat all of our subcontracted engineers are Gas Safe registered and can service your boiler swiftly and safely. Prices of an expert boiler service with iHeat start from £99.These figures might fluctuate regionally and can also depend on the specific type of boiler you own, such as a combi, gas, or oil boiler. 

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iHeat New Boiler Cost

Boilers can be a daunting purchase for many people as they’re an appliance with a lot of responsibility, providing heat for you and your family is something you want to get right. Boilers aren’t exactly a quickly disposable item either, potentially lasting you a decade.

Effectively, new boiler cost can be split into two segments: the first is the actual boiler itself (unit price), and the second is the cost of the boiler being installed (set up) in your property by an expert engineer. 

Here at iHeat, we remove all of this undue stress and make the decision making process of upgrading to a new heating system, as easy as possible.

New boiler costs can vary depending on a number of factors including their brand, model, fuel, output, warranty, labour and boiler installation type. Typically a new boiler will cost between £1,845 and £3,500, below is a list of average boiler installations offered by iHeat (guide only).

Installation Type

Price (inc VAT)

Combi to combi swap


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System to combi conversion


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New boiler install


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Back boiler to a combi


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System to system


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Frequently Asked Questions

How do I restart my Vaillant boiler?

To restart a Vaillant boiler, locate the reset button on the control panel. Hold the button for 3 seconds until the display indicates the boiler is resetting. Be careful not to press the button multiple times to avoid damaging the control panel.

Is it safe to reset Vaillant boiler?

Yes, it is generally safe to reset your Vaillant boiler if you follow the manufacturer's instructions. Make sure to check the manual for specific steps and warnings. If unsure, contact a professional to avoid any potential risks.

Can I reset my boiler myself?

You can reset your Vaillant boiler on your own by following the user manual. Hold the reset button for 3 seconds without repeatedly pressing it. If the problem persists, consider calling a qualified technician.

Why is my Vaillant boiler not firing up?

A Vaillant boiler might not fire up due to frozen pipes, power supply issues, or a need for resetting. Frozen water in the pipes can block the system, while electrical issues might require checking the fuse box for any tripped circuits.

How do I fix my boiler not firing up?

To fix a non-firing Vaillant boiler, start by checking for frozen pipes and thaw them if necessary. Verify the power supply and reset the boiler by holding the reset button for 3 seconds. If these steps don't work, consult a professional.

What causes a boiler not to fire up?

Several factors can cause a boiler not to fire up, including frozen condensate pipes, power interruptions, or internal malfunctions. It's essential to check each potential issue systematically to identify the root cause.

How do I get my boiler to fire up?

To get your boiler to fire up, ensure there are no frozen pipes and the power supply is stable. Hold the reset button on the control panel for 3 seconds. If the boiler still does not fire up, it may need professional servicing.

Stephen Day profile photo
Article by
Stephen Day | Co-founder
Gas Safe registered and FGAS certified engineer with over 20 years experience in the heating and cooling industry.