Has your boiler stopped working and Has your Vaillant boiler locked out and presented you with the F24 error code? Here are the most common causes and fixes.
Like boiler brands across the board, Vaillant’s boilers come with a ton of built-in fault codes.
These codes will appear when there is an issue with your boiler and the specific code figure tells you what the exact problem is.
With the Vaillant manual, homeowners can determine what any given fault code means and seek a possible solution.
While some Vaillant faults can be fixed DIY, others must be solved by a professional.
But what about the F24 fault code in particular?
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What Does F24 Mean?
An F24 error code appears because water is not circulating through your heating system’s pipework as it should be.
This leads your boiler to malfunction; it shuts down for safety and to protect its functionality while displaying an F24 code.
Of course, water is instrumental to a heating system working since it is needed to heat up radiators and for the provision of hot water such as for showering.
When an F24 fault code appears, it is because either there is no water circulating through your heating system or very little.
Why Is There Little or No Water Circulation?
There are several potential explanations for why there is a lack of water circulating through your heating system.
Here are the likely causes:
Faulty Pump - One of the most likely reasons for a lack of water circulation in a heating system is a faulty pump. This can be the result of debris in the pump leading to a blockage or seized components or incorrect speed settings. It’s also possible that components have seized for a reason other than debris, which again can lead to a pump fault.
Isolation Valves - If you had your boiler serviced in the recent past, it’s possible that the isolation valves were left in closed positions by mistake. This would stop water circulating and lead to an F24 error code.
Airlocks - Another possible explanation is trapped air somewhere in the heating system. This can slow or even stop water flow leading to an F24.
Faulty Electrics - A less obvious cause of an F24 fault is if there is a problem with the wiring connecting the pump and PCB. This can lead to problems such as an F24 error being triggered, and whether or not there is actually an issue with water circulation.
Can I Fix an F24 Error DIY?
In most cases, an F24 fault must be fixed by a professional, however, it depends on the cause.
If you’ve no idea what the cause is, you should hire a heating engineer.
Isolation Valves - Possibly, yes
If you suspect this is the issue, you can remove your boiler casing and check to see if the isolation valves are turned to the closed positions.
If they are, carefully turn them to the open positions.
Faulty Pump - No
This cannot be dealt with by a DIYer. Whether it relates to speed settings, debris, or seized internal components, a Gas Safe Register engineer must fix this.
Airlocks - Generally, yes
Thankfully, airlocks can usually be fixed DIY. This can be achieved by bleeding your radiators.
Bleeding radiators involve the following:
Make sure your heating is off. It should be, of course, if your boiler has an F24 fault. All in all, your radiators need to be cold before you bleed them.
Put a towel and basin under the bleed valve of the initial radiator you want to bleed.
Place a bleed key into the valve.
Gradually turn it counterclockwise.
You’ll notice a hissing noise while air begins to escape.
As the water starts to exit via the bleed valve, you need to turn the key back to its initial position, turning it clockwise until the valve is closed.
Repeat this process for other radiators.
Once everything is done and safe to go, you might need to reset your boiler for the fault code to disappear.
Faulty Electrics - No
This is another case where a professional must fix an issue. Faulty electrics must be dealt with by a person with the right qualifications.
It is both illegal and dangerous for a DIYer to take this on by themselves.
Related boiler guides:
Cost of Hiring a Heating Engineer to Fix an F24
The pricing of hiring a heating engineer to perform fixes to an F24 error will depend on the exact issue at hand.
However, in general, Gas Safe Register engineers charge around £30 to £60 per hour, although even this labour fee can depend on factors such as where you’re located.
Here is the estimated cost of different fixes for an F24:
Isolation Valves - £30 to £60
Replacing a Faulty Pump - £200 to £300
Bleeding five to ten radiators - £80 to £120
Bleeding ten to twenty radiators - £100 to £200
Repairing/replacing Faulty Electrics - £100 to £250
New boiler installation - £800 to £2,800
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:
Will my Warranty Cover Repairs or Replacement?
Unfortunately, it’s pretty unlikely that your Vaillant warranty will cover a repair or replacement job in relation to an F24 fault code.
In fact, in general, these warranties apply only if a repair relates to a manufacturing default with the boiler.
As a result, their warranty does not apply in most cases.
In addition, even if a manufacturing error is present, the following considerations must be taken into account:
Your boiler warranty must still be valid. Vaillant warranties can vary depending on the specific appliance.
Specific terms and conditions also cover Vaillant warranties such as that it must be serviced by a Gas Safe Register engineer annually.
Is your Vaillant boiler experiencing some of the brand's most common fault codes? We have many covered many Vaillant boiler error codes in the following guides:
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