Vaillant Boiler F61 Fault Code Explained [And What To Do Next]

Are you seeing F61 on your Vaillant boiler display panel, and has your boiler locked out? Then you’re in the right place — this guide will help you figure out what the error code means and what to do next.

Why You’re Seeing F61 on Your Vaillant Boiler

Put simply, the Vaillant F61 fault code points to a gas valve fault. You’ll need to book in a Gas Safe engineer to find and fix the fault, as they’re the only people that are qualified to work on gas appliances.

Why Your Boiler Locks Out When Displaying the F61 Fault Code 

A boiler with a gas fault is potentially dangerous. Your PCB (Printed Circuit Board) monitors a range of sensors to determine whether your boiler is working safely and efficiently. If it detects an issue with the gas supply, it will lock the boiler out as a precaution, and display “F61” on the screen.

What Causes the Vaillant F61 Fault Code 

If you’re seeing F61 on your Vaillant boiler’s display, the most likely explanation is that the gas valve has become stuck or is completely seized. Since valves are mechanical in nature, this is an entirely natural occurrence.

That said, in other cases, the problem could relate to wiring issues or even a communication error with the boiler’s main circuit board.

  1. Stuck & Seized Valves

If the Vaillant F61 error you’re getting signifies a stuck or seized valve, there could be 2 complications. If the valve is partially stuck open, it could be letting gas into the combustion chamber when it shouldn’t; this is potentially dangerous. And when it’s working on the flip side (stuck partially closed), it’s starving your boiler of gas.

Luckily, in most cases, these valves can be freed. As we’ve mentioned above, you’ll need to book a Gas Safe engineer and they’ll be able to asses the situation. If the valve can’t be completely freed, it’s likely they’ll suggest a replacement.

  1. Problems with wiring and connections

Another common reason you may be seeing the Vaillant F61 fault code has to do with wiring and connection faults. 

Wiring can easily come loose because boiler parts such as the pump and fan vibrate. Likewise, connections can be come damaged, sometimes due to old age, or on other occasions because of further problems with your boiler, such as leaks.

Small issues with wiring and connections can be fixed and secured. But if in doubt, your Gas Safe engineer will simply replace the valve (sometimes this is less than the cost of labour for a repair).

  1. Faulty gas valve

If your Vaillant F61 error points to a faulty gas valve, bad news — you may have to replace the valve altogether. Unfortunately, not all gas valves can be fixed; sometimes, the combination of wear and damage means that fixing the component isn’t cost effective.

Your boiler engineer will be able to test the valve and determine if this is the case. If so, unfortunately a replacement is going to be needed.

  1. Printed circuit board fault

We’ve seen instances where the Vaillant F61 fault is nothing to do with the gas valve, even though that is the stated cause.

If your engineer is confident the valve isn’t the problem, then it’s likely an issue with the wiring harness that connects the gas valve to the PCB.

The PCB is the control hub for your boiler, and all electronic parts rely on it for signals, so they know exactly when to operate (and when to cease operation). If there’s a problem here, your boiler will simply lockout.

Unfortunately, the cost of a PCB replacement can sometimes be as much as £500.

If your boiler is out of warranty and needing repairs of this magnitude, in general, it makes sense to consider a replacement.

You can get on-screen prices for a replacement boiler here in less than 90-seconds.

Getting the F61 on Your Vaillant? Here’s the Cost to Replace Your Boiler Gas Valve

As we’ve mentioned above, in some scenarios you can fix your boiler gas valve. But, if your Gas Safe engineer thinks there’s even the slightest chance of the fault persisting, you’ll need to replace it instead.

The overall cost of a replacement will be in the region of £300 (depending on the boiler model).

If your engineer finds that your boiler and other parts (such as the fan, pump, and PCB) are on their way out, it might be time to consider a replacement boiler instead of a repair.

You can get great deals on boilers through Heatable by filling out a simple on-screen form; it takes less than 90-seconds.

What’s Next?

Still getting the Vaillant F61 fault code? Or is your Vaillant boiler showing more than one fault code and your engineer can’t find the problem?

Check out our guide to other Vaillant Boiler problems, or directly check out what the f75 code error means and the f28 fault code. Or drop us a line via our contact form and we’ll do our best to help you out.

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