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Vaillant F75 Fault Code: Causes & How To Fix

Vaillant F75 fault code – What it is & how to fix it


Vaillant is one of the top boiler brands in Europe, producing some great models of boilers and other heating appliances. Their boilers are very popular in the UK due to their high quality, but sometimes they can have faults, such as the Vaillant F75 fault code.

This error code usually means that there is an issue with the pressure of your boiler, which will probably cause your boiler to perform an emergency shutdown. Don’t worry though, you don’t need a new boiler just yet, this can get resolved in a few ways.

The best thing to do might be to call out a Gas-Safe registered engineer to your property to have a look at your boiler and determine what is wrong as well as what they can do about it.

Fill in the form below to get Gas-Safe registered engineer to service your Vaillant boiler

How to fix a Vaillant F75 fault code

Whenever you see the Vaillant F75 error code, it will usually be caused by one of 2 things: a clogged pressure sensor or a faulty pump. Either way, your boiler will likely do a boiler lockout to help prevent the boiler from getting more damaged or potentially harming anyone in the household.


Calling a qualified engineer to look at the boiler for you will likely be the best course of action, as looking at it yourself could potentially be dangerous or further break the boiler. A Gas-Safe engineer will have the knowledge and experience in this situation to properly sort out your boiler for a reasonable price.

Getting Vaillant boiler warranty may also be a good idea if you own a Vaillant boiler, as it could end up saving you much more money long-term. Boiler cover may be able to help with the costs of part replacements and the repairs that your Vaillant boiler needs.

What a Vaillant F75 fault code means

If you were to get this error code, as previously mentioned, it means that there is no pressure change when you fire your boiler up. A fault with your boiler’s water pressure would cause it to likely stop working correctly and, with your water having low pressure, your hot water needs may not be met.

There are a few reasons why your boiler pressure is faulty and the Vaillant F75 fault code has appeared. Here we will go through them to show you how it happens and what you can do about it.

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Causes for Vaillant F75 error code

Defective water pressure sensor

fixing water pressure

When using your boiler, over time many components can have a build-up of debris from carbon and limescale, which can cause that part to not work properly. This is something that can also happen to your water pressure sensor, as all of the build-up could cause the signal to be off and sense the water pressure correctly.

A faulty pressure sensor could mean that you don’t get any hot water, even if you can hear the heating pump working. If this is the case, then getting it fixed as soon as possible is the best thing to do, as it won’t only allow you access to hot water again, but will mean you aren’t wasting money paying for something you can’t even get.

Fixing a faulty pressure sensor

boiler parts

If you have found that you have a blocked pressure sensor due to a lot of limescale and debris, then you should clean this to the best of your ability, so that the pressure sensor is able to work again and the signal isn’t blocked. Once you have done this, just reset your boiler and everything should be back up and running.

If it is a completely broken pressure sensor, the most common course of action is to get a new pressure sensor rather than getting it fixed by a Gas-Safe engineer. Due to their low cost, most people opt for this, as they won’t have to worry about this being a problem again for a while.

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Faulty boiler pump

Your central heating pump is a vital part of your boiler as it will push hot water through your central heating system to make sure it gets to the appliances it needs to, such as radiators or your shower. When your boiler pump is broken or faulty, this heat won’t be pushed around your system meaning very little to no access to hot water.

To find out if a faulty pump is the problem, you can take the following steps:

  1. Press the reset button to reset your boiler.
  2. After waiting a few minutes, run your hot water tap to fire up your Vaillant boiler.
  3. Once you’ve done this, the boiler pump should start to send hot water through to your tap.
  4. If there isn’t any water coming through, this means that you have a faulty pump.
  5. If water runs through for around 20 seconds and then stops, this means that a faulty sensor is the issue rather than your heating pump.

Fixing a faulty boiler pump

broken boiler pump

If your pump is the problem, then the best thing to do is to get a Gas-Safe engineer out to your property and examine it, rather than try to fix it yourself. This is due to them having the tools, knowledge and experience in dealing with broken pumps, whereas doing it yourself may risk making it even worse or potentially harming yourself.

The price of getting a replacement pump is usually between £150-£300, including installation and without Vaillant warranty. Although this may seem like a pricey investment initially, it is still cheaper than having to buy a new boiler, so is well worth it.

Other common Vaillant fault codes

Vaillant boiler service

Getting your Vaillant boiler serviced annually is the best way to stay on top of issues such as the F75 fault code and other common fault codes. Vaillant boiler service will mean an engineer can regularly examine and monitor your boiler and then inform you if there is anything that is in need of repair.

boiler service

If it is, they can then repair or replace any components necessary so that your boiler can be at its most effective. If you have Vaillant boiler warranty, a lot of these repairs may be covered by this meaning you won’t be paying extortionate amounts just to keep your central heating running.

The average cost of a boiler service is between £80 and £125, with this price changing depending on a few different factors. These include the size of the boiler, the model, the type of boiler and how old it is, as this can change how long the service takes or how much work is required.

Although this may seem a lot to pay in one go, it will actually be much cheaper to regularly service your boiler rather than waiting and allowing problems for Vaillant boilers to build up and get worse.

How to avoid Vaillant F75 error code

As mentioned before, getting regular boiler service will help avoid this issue and other error codes like it. This will allow an engineer to check if there is anything wrong with your boiler whilst it is in operation as well as clean all of its components to prevent build-up.

With your boiler being clean, there is less chance that any fault codes regarding dirty parts or blocked pipes occur, so despite the price, it is very much worth it.

Fixed prices for Vaillant boilers

If you keep having problems with your Vaillant boiler, then this may be a sign to get a boiler replacement, which could spare you from a lot of the issues you were facing. It could also be much more financially rewarding for you, as you won’t be paying tons of money for repair costs all the time.

Find out more about new boiler quotes online for Vaillant boilers.

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