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Vaillant F22 Error / Fault Code Explained & How to Fix

The Vaillant F22 error code (also Vaillant F.22 error) means that the boiler is low on water pressure and needs to be increased to work again.

A Vaillant boiler will only work when it has the required water pressure, which should be around the 1.5 mark on the built-in pressure gauge. Should the pressure drop to 0.3 bar, your Vaillant boiler will display the F22 error code and lock out so your central heating and hot water won't work.

Vaillant defines the F22 error message in the following way:

Vaillant Fault Code Meaning Possible Causes
F22 / F.22 Low water pressure There's little to no water in the system which could mean that there's an issue with the pump or the pump lead is defective.

Fixing the Vaillant F22 error code is something that you could attempt yourself but a Gas Safe engineer would be able to take care of it quickly and safely. You can get free quotes from Gas Safe engineers near you today using Boiler Guide.

Vaillant F22 fault code: Common causes

Without enough water pressure, your boiler won't ignite so it's important to find the cause. Boilers naturally lose pressure over time but this will be a very gradual progression. If you've noticed a sudden drop in boiler pressure, there could be a leak somewhere in the system.

A leak is something that you shouldn't attempt to repair yourself – always hire a professional heating engineer. Should you locate a leak, which could be around the boiler, by radiators or anywhere around your home fitted with pipes, turn off the water supply to prevent damage to your home.

In addition to a leak, one of the components within the boiler, such as the pump, the pump lead or a defective pressure sensor. You should leave diagnosing and, if required, replacing these parts to a fully-qualified heating engineer.

Fixing the Vaillant boiler F22 fault

To resolve the Vaillant F.22 error and get your boiler working again, the pressure needs to be increased, which you can do yourself.

To increase low boiler pressure, start by switching the boiler off and waiting for it to cool down. You then need to find the filling loop, which is commonly found under the boiler, and can be identified as the metal hose with a valve at either end. Turning these valves will allow water to enter the boiler, watch the pressure gauge at this point and turn the valves back to their original position once the needle reaches 1.5 bar.

More Vaillant boiler error codes

A common error message seen on Vaillant ecoTEC boilers is F75. Get your Vaillant ecoTEC back up and running with our guide to the Vaillant F75 fault.

If your Vaillant boiler won't ignite, then it's likely that you'll see the F28 fault code.

Quick F22 fault code repair

As a Vaillant F22 error will leave your home without heating and hot water, you'll want the issue to be resolved as quickly as possible. The quickest, and not to mention, safest way of fixing the Vaillant F22 error, is to hire a Gas Safe engineer.

Complete our simple online forms, which shouldn't take long at all, and you'll soon get free quotes from up to 3 local heating engineers who are all fully-qualified to repair the Vaillant boiler F22 error and get your central heating and hot water working again. The reason we get up to 3 heating engineers to contact you is so that you can compare multiple quotes, putting you in the position to pick the best deal for you – much better than getting the 1 quote.

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Boiler Guide Team

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Boiler Guide Team

Boiler Guide has been home to a host of heating experts who have helped millions of UK homeowners searching for advice and guidance. If you’ve got heating questions, we’ll have the answers.

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