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Vaillant F22 Fault Code: Causes & How To Fix

Vaillant F22 error code – how to fix it & what it is


Vaillant is a well-known boiler and heating appliances brand all throughout the UK and Europe, producing some of the best boilers on the market right now. Even with the great technology and engineering these boilers have, they can sometimes fail and error codes appear, like the Vaillant F22 fault code.

This is one of the most common error codes that can be displayed on your Vaillant boiler, meaning that it is quite an easy fix and a boiler replacement isn’t necessary just yet. When the F22 fault code appears, it means that your boiler is losing pressure and needs to be topped up.

In a lot of cases with Vaillant boiler fault codes, you can get a Gas-Safe registered engineer to come to your property to examine and fix any issues you are having with your central heating system. However, there are a few that can be fixed by you and don’t require a heating engineer, so here in this guide, we will go through what to do.

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How to fix a Vaillant F22 error code

boiler parts

As mentioned before, whenever you see a Vaillant F22 fault code, this means that your boiler is experiencing low water pressure, which means that your hot water demands likely won’t be met. With low pressure, heating won’t be able to flow through your heating system as well, meaning showers and radiators won’t be as efficient.

Getting your boiler pressure back up to the recommended range is quite simple, you just need to use the external filling loop that your boiler has. We will go through the method step-by-step here:

  1. Find the filling loop, which is usually located at the bottom of your boiler underneath it.
  2. There should be two valves on either side of the loop, so open both valves to allow water to flow through to the boiler from the mains water supply.
  3. Wait for your boiler pressure to rise to 1-1.5 bars on the pressure gauge, making sure it doesn’t go above this range as this can also cause issues for Vaillant boilers.
  4. Once this is all done, close the valves on the filling loop and press the reset button on your boiler, as everything should now be up and running again.

If you aren’t feeling very confident in doing this yourself, you can always contact a Gas-Safe engineer to do it for you, as they will have the knowledge and experience of doing this before.

What a Vaillant F22 fault code means

gas-safe registered

Having high or low water pressure can be quite an inconvenience for your Vaillant boiler, so getting it fixed as soon as possible is always in your best interest. However, it isn’t always as easy as putting the pressure back up, as there can sometimes be alternate causes of your boiler pressure dropping.

Some of these may require help from a registered Gas-Safe engineer, depending on the severity of the cause. Here we will go through them and let you know what you should do in these situations.

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Vaillant F22 error causes

Faulty pressure sensor

Your water pressure sensor is a component of your boiler which will let you know if you have the correct pressure in your boiler. However, if this is damaged or faulty then your pressure sensor will send the wrong signals to your PCB, which controls the electrics of your system, so it may tell you your boiler pressure is fine when, in reality, it isn’t.

A faulty sensor can be quite hard to fix without a Gas-Safe registered engineer and even then, the best course of action is to just replace your water pressure sensor. They come at a relatively low cost, so replacing them is easy and will give you peace of mind when your boiler is in operation.

Leak in central heating system

leaking boiler

Sometimes the cause of insufficient water pressure is a leak somewhere in your heating system, meaning your hot water can’t flow properly through it. Make sure to look all around the different parts of your system to try and identify the leak as even the smallest one can cause pressure issues.

Attempting to fix a leak can be rather difficult, due to it requiring the tools and knowledge of what to do to repair it. In the case that you do have a leak, it is probably best to contact a gas engineer to identify and repair it for you, as they will have what was previously listed. It will also mean you can’t potentially further damage the boiler or harm yourself trying to fix it.

Your boiler pump, heat exchanger, radiators and pipework are the most common places to find a potential leak, so you should probably look at these to start with.

Water pressure drops & heating system

We went through what to do when your pressure drops, but making sure you know what to do is quite important so you don’t cause any further damage. Getting a gas engineer to do any of this for you is probably the way to go if you don’t have the confidence to do so yourself.

When your boiler does lose pressure, your boiler can lock out, meaning it performs an emergency shutdown to control the damage done. Usually, when your pressure goes below 0.5 bars, it will perform this lockout.

Other common Vaillant fault codes

Vaillant boiler service cost

Getting Vaillant boiler service is a great way to avoid error codes such as this one and keep your boiler running as effectively as possible. Modern Vaillant boilers will usually last around 10-15 years, so servicing can help you get the most out of it through this period of time.

boiler service

A lot of the time, to keep your Vaillant warranty valid, you will have to service your boiler at least once a year. Servicing will also mean that your boiler’s components are kept clean to stop blockages and other parts are examined to see if they need repairing or replacing.

This allows you to stay on top of any issues you might have, such as the Vaillant boiler F22 error code, meaning you can avoid constant breakdowns or lockouts.

The usual cost of a boiler service is between £80 and £125, which can vary depending on some factors. These include the type of boiler it is, how old it is and how big it is, with older and larger boilers probably taking more time to service and, in turn, costing more.

This may seem a lot to pay in one go, but getting annual service can actually end up costing less than allowing your boiler to constantly break and need fixing. Long term it is much more financially beneficial, so make sure to get your servicing done regularly.

Fixed prices online for Vaillant boilers

If the Vaillant boiler F22 fault or other error codes are continuously happening, this may be a sign that you need a new boiler. Getting rid of your old boiler and getting a brand-new Vaillant boiler can help stop any issues you keep having and actually be better for you financially.

Get an online boiler quote for a new Vaillant boiler.

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