And you thought 27 was bad. Welcome to the emporium of Vaillant F28. Let's explain this fault, and who's at fault.
- What causes the Vaillant boiler F28 error?
- Can I Fix This Error Fault Code Myself?
- Do I Need to Contact a Gas Safe Engineer to Fix the F28 Fault Code?
- Common Reasons Why This Error Code Appears
- How To Fix The Ideal F28 Boiler Fault Code
- How Much Will It Cost To Repair The F28 Fault Code?
- Do You Need A New Boiler?
A Vaillant F28 is a false start, literally.
Delve down below to reveal your immediate boiler destiny and the reason you're this deep in Google.
It's most likely going to need a boiler engineer visit (but there is one reason which might save you that fate).
Key takeaways:
F28 Error Code: Indicates an ignition problem where the boiler fails to ignite after three attempts.
Common Causes: Possible issues include gas supply problems, a faulty gas valve, or an ignition electrode issue.
Basic Troubleshooting: Check the gas supply, reset the boiler, and ensure there’s no blockage in the flue.
When to Call a Professional: If the problem persists after troubleshooting, contact a gas safe engineer for further inspection and repair.
In many cases, upgrading your old boiler to a new, more efficient model is the best solution.
Get a new quote (finance available including 0% APR).
What causes the Vaillant boiler F28 error?
The Vaillant boiler F28 error code is displayed on the following Vaillant boiler models:
ecoTEC Pro Plus
Turbomax Plus 824/828E
The F28 code is displayed when your boiler fails three ignition attempts, resulting in the boiler halting operation and turning off.
Vaillant officially defines the F28 error code as an ignition fault. There are many potential causes to this problem including an insufficient supply of gas, a faulty electrode or ignition lead.
Currently, the manufacturer doesn’t acknowledge the heinous work of gremlins.
Therefore, the causes of the F28 fault can be broadly categorised into either an ignition fault or a gas valve fault.
This issue results in a boiler failure, as ignition is required to light the gas and create the flame that warms the cold water.
Since it is faulty, the hot water can no longer become heated, meaning no hot water can be supplied to your taps or your central heating system.
If you’re the first in your house to spot the F28 boiler error, you might still get a shower if you don’t tell anyone else first.
Think you may have an ongoing issue with your boiler? Check our list of the top 10 boiler problems common in all types of boilers.
Can I Fix This Error Fault Code Myself?
Before calling a professional, you can try a few simple DIY checks and fixes to potentially resolve the issue:
Inspect the flue for obstructions – Ensure there are no blockages that could be restricting airflow, as this can prevent the boiler from igniting properly.
Verify the gas supply – Check that your home’s gas supply is functioning correctly by testing other gas appliances. If they are working, the issue is likely boiler-specific.
Reset the boiler – Follow the manufacturer’s instructions to perform a reset, which may temporarily resolve the fault and restore heating.
If the fault persists after these steps, professional assistance will likely be required.
Do I Need to Contact a Gas Safe Engineer to Fix the F28 Fault Code?
Yes, it is essential to contact a Gas Safe registered engineer to resolve the F28 fault code. These qualified professionals are legally certified to work on gas boilers and will ensure that any repairs are carried out safely and in compliance with industry regulations.
Attempting to fix complex boiler issues without professional expertise can pose safety risks and may void your boiler warranty.
Common Reasons Why This Error Code Appears
When diagnosing the cause of the f28 fault code on your boiler, a registered Gas Safe Engineer will likely inspect the following boiler components:
Gas supply issue
One of the most common causes of an f28 error code being displayed is a gas supply fault.
i.e. no gas supply to your boiler
It’s really just the boiler equivalent of missing your own mouth with a spoon while eating.
You can easily test if this is the likely cause yourself by attempting to turn on other gas appliances in your home and seeing if they work or not.
i.e. a cooker, or fire
If there is no gas supply, this may be caused by your energy company cutting off supply, gas infrastructure work currently taking place in your area, or you may have simply not topped up your meter (if you have one).
Looking to pay for your new boiler monthly? Refer to our boilers on finance guide.
Faulty gas valve
A gas valve fault is another common cause of an F28 error.
Image showing a standard gas valve
The gas valves' main role is to control the supply of gas into the boiler, so when there is an issue no fuel can be ignited to heat the water.
A fault with the gas valve can be a result of either a wiring or mechanical fault.
Unfortunately, nobody can help you with Uncle William’s faulty gas valve - just limit his onion intake.
Cost to fix: £150-300
Wiring fault
For example, boiler components are connected electronically to the printed circuit board (PCB), which is the control centre of the boiler, responsible for controlling and coordinating the various boiler components.
Image showing standard wiring
Think of it as your boiler’s brain - a wiring fault in your brain also comes with plenty of errors.
Therefore, if a wire is loose or disconnected between the gas valve and PCB, the signals will no longer be transmitted, resulting in the gas valve malfunctioning, and causing the boiler to shut off.
Cost to fix: £100-500
Is your boiler leaking or losing pressure? Use our quick and easy tool to get your fixed price boiler replacement.
Mechanical fault
Alternatively, the gas valve may not be working due to a mechanical fault. With time, the valve becomes susceptible to wear and tear, resulting in it sticking.
A gas valve that is prone to sticking will no longer be able to reliably carry out its function – to open and close whenever gas is required. As a result, this can cause the boiler to shut off and display the f28 error code.
Cost to fix: £100-300
PS You may be interested in Gas Engineer Allen Hart explaining the most common boiler problems and how you can resolve them in the video below:
Faulty electrodes
When the gas enters the boiler via the valve, it needs to be ignited by the electrodes, however, if they are faulty, they will no longer be able to ignite the gas and create the flame.
Image showing a standard electrode
Your faulty electrodes just grew apart. They stopped truly caring and putting in the effort in the early days. Maybe they’re just tired at night - maybe they’re stressed at work. But the romance is gone, and they can’t seem to ignite the flame.
Maybe we’re overthinking this.
Over time, the electrodes can become worn and may need to be cleaned or replaced, in which case a registered Gas Safe Engineer can do this.
Cost to fix: £100-300
Frozen condensate pipe
The condensate pipe’s job is to direct toxic flue exhaust fumes/vapour/residue to the outside of your property, so when this becomes blocked it can be a safety hazard, hence why the boiler will shut off until the issue is resolved.
Image showing a standard condensate pipe
When it comes to a frozen condensate pipe, it’s either cold showers or toxic fumes, and you don’t get to choose.
Traditionally, condensate pipes tend to freeze in winter, resulting in a blocked pipe. To resolve this, a Gas Safe Engineer can defrost the pipe to get the contents flowing again.
You can attempt to do this yourself too, check out our quick DIY YouTube video below:
Additionally, modern boilers such as Worcester Bosches Greenstar Range are equipped with CondenseSure, this is a feature designed to prevent condensate pipes from freezing.
Cost to fix: £50-100
PCB fault
The printed circuit board is the processing unit of the boiler and is wired up and receives signals from many of the boiler’s components, controlling their function and ensuring they coordinate together as intended.
Image showing a standard PCB
However, if a wire is loose or disconnected from a component and the PCB, or the PCB is faulty, it could result in the boiler shutting off and displaying the f28 error code.
For Mother’s Day this year, we recommend getting your mum a card that says “You’re the printed circuit board of this house”. You can thank us later.
Cost to fix: £100-500
Check our new boiler costs guide and use our boiler size calculator if you want to get a better understanding of how our fixed-price boiler quote tool works.
How To Fix The Ideal F28 Boiler Fault Code
If you’re experiencing the Vaillant F28 Boiler Fault code, it indicates a gas supply or ignition issue. You can try the following troubleshooting steps to resolve the issue:
Reset the boiler - Try resetting your boiler by turning it off and on again. Some models have a dedicated ‘reset’ button—refer to your user manual for instructions.
Check your gas supply - Ensure your gas supply is functioning by testing other gas appliances in your home. If they are working properly, the issue is likely specific to the boiler rather than the gas supply.
Inspect the flue and air intakes - Check for any blockages or obstructions in the flue or air intake pipes, as these can prevent the boiler from igniting.
Seek professional help - If the F28 fault code persists after trying these steps, it’s best to contact a Gas Safe registered engineer. The issue may be caused by a faulty ignition system, gas valve, or another internal component that requires expert diagnosis and repair.
How Much Will It Cost To Repair The F28 Fault Code?
The cost of repairing an F28 fault code typically ranges between £150 and £300, depending on the root cause of the issue. Several factors influence the final repair cost, including the complexity of the fault, required replacement parts, and the engineer’s call-out fees.
Factors That Can Affect the Repair Cost:
Severity of the Issue - More complex faults, such as a faulty gas valve or ignition failure, may require additional time and costly replacement parts.
Location - Repair costs can vary significantly depending on your region, with higher rates often seen in major cities compared to rural areas.
Urgency of the Repair - Emergency or out-of-hours call-outs usually come with higher service charges.
Addressing boiler error codes promptly not only helps maintain the efficiency and safety of your heating system but can also prevent more costly repairs in the future.
Is your Vaillant boiler experiencing some of the brand's most common fault codes? We have covered many Vaillant boiler error codes in the following guides:
Do You Need A New Boiler?
In some cases, replacing a boiler can make more financial sense than continuing to repair it. Here are the key factors to consider:
Age of the Boiler - If your boiler has surpassed its average lifespan (typically beyond 15 years) and is no longer covered by the manufacturer’s warranty, replacing it may be a more cost-effective option to avoid recurring repair expenses.
Repair Costs - When the cost of repairing the boiler exceeds 50% of the price of a new one, it’s usually more financially sensible to invest in a replacement rather than continuing with costly repairs.
Frequency of Breakdowns - If your boiler is breaking down more frequently, it’s often a sign of significant wear and tear and it is beyond economical repair. In such cases, replacing the boiler can help avoid mounting repair costs and the inconvenience of ongoing issues.
Energy Efficiency - Older boilers tend to be far less efficient than modern models, leading to higher running costs. Upgrading from a G-rated to an A-rated boiler could save you up to £385 per year in energy bills, making replacement a financially smart decision in the long run.
By carefully weighing these factors, you can determine whether replacing your boiler offers better value and peace of mind compared to continued repairs.
Learn all about combi boilers in our what is a combi boiler.
Get a Quote for a New Boiler Today
The best way to resolve the F28 error code is to seek the help of a registered Gas Safe Engineer, who will be able to diagnose and repair whatever is causing the f28 code to be displayed.
If you’re aiming to get the best deal on a new boiler, consider getting your boiler installation with us. Here’s why:
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Flexible payment options, including interest-free finance.
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