F22 Vaillant Boiler Fault: What Does F22 Fault Code Mean and How to Fix It?

Vaillant boilers are reliable devices that’ll serve their owner quite well for a long period of time. However, like anything in this world, it’ll eventually start exhibiting problems, and what better way to communicate said problems than error codes?

That’s why we’ll be discussing the F22 fault code in this article. We’ll tell you everything about it, from what it means to how you can fix it. So, keep reading to learn how to get rid of that annoying F22 error code.

What Does the Vaillant F22 Error Code Signify?

In simple words, the Vaillant F22 error code indicates that the water pressure in your Vaillant boiler has fallen significantly low.

This means there isn’t nearly enough water circulating in your heating system, and therefore, the boiler won’t be able to ignite, and it’ll stop working. Then, it’ll show you the F22 error in hopes of you restoring the proper pressure.

However, to raise the pressure, you need to find out why the pressure drop happened in the first place. Was it a once-in-a-blue-moon thing, or is there an actual issue with your heating system somewhere? So, let’s see what can go wrong with a Vaillant boiler so that you can hopefully diagnose the problem with your own boiler.

Possible Causes for the F22 Error Code on Vaillant Boilers

There are actually many reasons why your boiler may be showing you the F22 error.

For one, it can be an issue with the boiler itself, specifically its pump or its water sensor. The problem could also lie with your heating system, where a small leak could be messing with the water pressure. So, let’s take a closer look at all those issues and see if you can discover which one your boiler is suffering from.

Leaks in the Heating System

If you’ve looked at your pressure gauge and noticed a sudden significant drop, it’s highly likely that there’s a leak somewhere in your central heating system.

It can be in your pipework, towel rails, radiators, or the actual boiler, and it’s usually due to pinholes or loose joints, though it’s worth noting that bleeding your radiators will also cause the pressure to fall.

Unfortunately, a leak means water damage to your boiler components, and if it’s not detected promptly, it also means significant damage to your walls and floors. So, if you suspect there’s a leak somewhere, you need to intervene as soon as possible to spare yourself the considerable repair bill.

Faulty Boiler Pump

Another culprit for the drop in pressure is a faulty pump. If the pump isn’t working as it should, then water won’t reach your boiler and heating system, resulting in low water pressure.

Defective Water Pressure Sensor

Now, suppose your Vaillant boiler is showing you the F22 error code, but when you come to look at the pressure gauge, you find that it’s within the correct range. In that case, your water pressure sensor is the offender.

Quite simply, the sensor isn’t working well, so it sends bad signals to the electrical board of your boiler. Accordingly, the board will interpret the wrong signals as a lack of pressure, and the F22 code will magically appear.

To ensure you have a faulty sensor, simply look at the pressure gauge and see if the supposed drop in pressure is real or not.

How to Fix An F22 Fault Code on a Vaillant Boiler

Though we mentioned a few different reasons why your Vaillant boiler may be showing the F22 fault code, some boilers simply lose pressure over time and simply need to be re-pressurised.

Lucky for you, almost anyone can top off their boiler in a few minutes. You just need to find the filling loop first, and then you can get to work re-pressurising your boiler.

Once you locate it, turn off your boiler and let it cool for a few minutes. Then, attach the filling loop, aka the metallic bose with valves on its ends, to your heating system. In some cases, you may need to take off end caps before attaching your loop to ensure that the loop is securely fastened.

Following this, open the valves so that water starts flowing into your heating system. At this step, you should hear water flowing into your boiler. If you don’t, then you’re doing something wrong, or there’s a problem with the pump or another major issue in your heating system.

Anyways, with the valve open, you’ll notice the pressure gauge rising. However, some air may enter the heating system and cause an obstruction. That’s why you’ll need another person to bleed the radiators while you’re filling the boiler.

Once the pressure gauge reaches the 1 mark, close the valves and remove the filling loop, and replace the end caps if you’ve previously removed them. Finally, keep a close eye on the pressure gauge.

If you notice another severe drop in pressure in less than a day or so, then you’ve got a leak in your heating system. In that case, you’ll need to call a professional heating engineer and have him locate and fix the leak.

F22 Vaillant Boiler Fault – To Sum Up

An F22 error on a Vaillant boiler means that there’s low water pressure. This can either be due to a leak in your heating system or a fault with the boiler’s component, such as the pump or the pressure sensor.

If you suspect a leak, then it’s imperative that you get a professional to look for it and have him repair it as soon as possible to avoid further water damage to your house and appliances. However, if the problem is with the pump or the sensor, then you can simply replace these components with the appropriate substitutes if you know your way around a boiler.