Vaillant Boiler F28 Error Codes (the causes & how to fix them)

It is important to look at your boiler to find the error or fault code in case you are having some problems with your Vaillant boiler.

What is a fault code?

A fault code is like a sign that would indicate what problem your boiler is having. It can make fixing the problem much easier considering that you know what the problem is. These signs should not be ignored or neglected.

In case of an existing problem, your boiler would turn itself off to prevent further damage. It is like a lockout protocol to keep your boiler safe.

 A Vaillant boiler has the ability to display an error code when there is something wrong with it. This code will provide you or the heating engineer with information regarding the problem your boiler is having. For example, one of the most common codes in a Vaillant boiler is Vaillant F28. On this page you will find what you need to know about the Vaillant F28 error code. We will cover everything. This will include what causes this and how to fix it.

The boiler manual instruction can also be a good guide to understanding these codes.

However, in some cases, getting a new boiler might be more cost-effective than getting your old boiler fixed. Some issues might be costly to fix. What is more, a new boiler will probably be more efficient and can help you save both money and energy. That is why getting a new boiler is a good investment in the long run.

Get a quote from Let’s Heat. We have a large range of products and our staff of Gas Safe engineers provide an excellent service that is both professional and reliable. In addition, we can help you get the boiler that best fits your house and heat requirements.

Read about: Common Sime Boiler Error Codes

A Brief History of Vaillant Boilers

Vaillant Boilers are known to be revolutionary, reliable as well as quiet.

Johann Vaillant has founded Vaillant in 1874 in Remscheid, Germany. Firstly, Johann Vaillant founded a workshop of his own as a copper beater and pump maker.

Vaillant has been credited for many inventions such as the modern-day central heating in 1924. In the past, each room was heated separately by using a stove or a fireplace. Then Vaillant came along and introduced central heating. A system that is able to heat multiple rooms simultaneously.

You can find out more about Vaillant boilers on these blogs:

Vaillant EcoTEC Plus System Boiler Review

Vaillant Combi Boilers Reviews

How to fix the Vaillant boiler F28 Error?

You will encounter the F28 code with the following models:

• Vaillant Ecotec Pro
• Ecotec Pro Plus
• Turbomax Plus 824/828E

The F28 code will be shown on these models after three failed ignition attempts by the boiler.

The first solution that can come to your mind is to turn off and on your boiler. But this will not work considering that your boiler is now in its ‘lockout’ mode. So this attempt would be futile. What you can do, however, is to get the services of a Gas Safe engineer. It is dangerous to try and fix the boiler yourself.

Read more: Main Boiler Error Codes / Fault Codes

What casues the Vaillant boiler F28 error?

To put it simply, the F28 code is an ignition fault. However, other underlying issues can also cause this code to appear. These might include Gas valve faults and Gas supply faults. Here’s a more detailed list:

• Condensate pipe
• Printed circuit board (PCB)
• The wiring harness to the gas valve/gas valve is mechanically sound

 A Gas Safe engineer is likely to inspect and check these first in order to be able to narrow down the causes and exactly know what the caused the issue and how it can be fixed.

What is the purpose of ignition in a boiler?

The ignition is important to light up the gas. Which can then starts the flame that is required to heat the colder water in your boiler.

When your boiler fails to ignite, then water can’t be heated. This, of course, will lead to cold water which will be running in your taps and heating system.

Read about: Navien Boiler Error Codes / Fault Codes

ATAG Boiler Error Codes / Fault Codes

Fixes of Vaillant boiler F28 error

1. Gas Valve

More than often, the cause of the F28 Vaillant boiler fault code is the Gas valve. Then they would look into the wiring harness to the gas valve and the gas valve function as well.

• Gas valve wiring

The aim of this wiring is to connect the gas valve to the printed circuit board (PCB). Both loose and damaged wiring can mean that the valve is not able to communicate with the PCB as it should be.

The PCB works by sending signals to the valve, informing it when to open and when to close. The gas valve will not be able to work without these signals. This can cause the boiler to shut down in some cases.

You do not have to worry about this issue as it is quite easy to fix. It does not take long to fix and is relatively cheap as well. A Gas Safe engineer can, without a doubt, fix this issue easily. As for the cost, it can be around £100.

• Gas valve function

Gas valves are prone to get stuck or, in some cases, wear out over the passage of time.

Your boiler will not be able to get the needed gas supply if the gas valve gets partly closed. As a result, your boiler will shut down and it will show the F28 error code.

If you gas valve is not entirely worn out, our gas engineer will be able to free it. However, if it is not, then it will be replaced with a new gas valve. A new gas valve can cost around £300. This price can include the part and the labour as well.

Read about: Common Sime Boiler Error Codes

2. Printed Circuit Board (PCB)

A Printed Circuit Board (PCB) is a very important part of your boiler.

To put it simply, the Printed Circuit Board (PCB) is the backbone which connects the boiler’s electrical components (like the pump, thermostat, timer and so on) together in one spot and enables them communicate together. Your boiler will completely shut down if the PCB stops working. The Vaillant boiler will lockout and shows the F28 code if the PCB stops sending the right signals to the gas valve.

Your PCB will be examined by running an electrical test. If there is a problem with your PCB, our engineer can either fixed it if it is possible or replace it if it cannot be fixed. The PCB can cost around £500, depending on various factors, such as the supplier and quality of the PCB. This includes the installation cost as well.

3. Condensate Blockage

If the condensate pipe gets blocked, it will prevent the condensed flue gases from passing out. This can be quite harmful.

When this occurs, the PCB would get a signal that the condensate pipe is blocked and, as a result, it will lock out the boiler. Then the code F28 will appear on your Vaillant. This issue usually occurs in winter when the toxic gases are prone to freeze in the pipe.

The Gas Safe engineer can defrost the pipe and ensure that it doesn’t happen again for just £50-100.

4. Faulty Vaillant Electrodes

Electrodes are used to ignite the gas in your boiler, but they will not be able to ignite the gas if they’re faulty.

Similar to other boiler parts, these electrodes can suffer wear and tear over time, which causes your Vaillant boiler to lockout and display fault code F28.

Your heating engineer can examine the electrodes and advise you if your electrodes need to be replaced or not. This might cost you some money.

5. No gas to your home

The code F28 could also indicate that there’s no gas being supplied to your home. This can be easily checked by turning on other gas appliances (i.e. cooker) to see if they work or not. As you can see, this is an easy problem that you can check yourself.  

If the other gas appliances aren’t working either, chances are your gas supply has been turned off. In such a case, you ought to call your energy company.

It might be worth considering getting a new boiler if you think that your current boiler is not worth fixing. A new boiler can save you more money in the long run as it is more efficient than older models. You can also take advantage of boiler finance to pay for your boiler.

Read more about:

Glow-Worm Boiler Error Codes / Fault Codes

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Ravenheat Boilers Error Codes / Fault Codes List

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