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Vaillant boilers are known for their reliability and efficiency. However, like any other appliance, they can occasionally encounter issues. One of the most common problems reported by Vaillant boiler owners is the F75 fault code.

Understanding F75 Fault in Vaillant Boiler

If you notice the F75 fault code displayed on your Vaillant boiler, it simply means that your boiler fails to detect a pressure change when the pump is activated. This fault is typically caused by a faulty pump or an issue with the water pressure sensor.

In addition to the F22 fault code, a leak in the connected pipes can also be a possible cause, although it is less common. This error code is usually accompanied by an audible alarm or flashing lights on the boiler's display panel.

Seek assistance from our boiler experts to resolve this issue promptly and efficiently.

What Causes F75 Vaillant Error Code?

There are a few potential causes for this error.
  • Faulty or Failed Boiler pump
  • Check boiler pumpOne of the most common causes of the F75 Vaillant fault is a malfunctioning or completely failed boiler pump. This pump plays a crucial role in circulating hot water throughout the heating system. When it's faulty, it prevents the boiler from registering a pressure change. In some cases, there may also be an issue with the water pressure sensor, which can result in the same error code.
  • A Defective Water Pressure Sensor
  • Check the water pressure pumpInadequate pressure within the heating system can also trigger this fault code. It's crucial to maintain the recommended pressure range, typically around 1 to 1.5 bars, for your boiler to function optimally.
  • Debris or Air Blockage
  • Check the water pressure pumpSometimes, the presence of debris or air bubbles within the heating system can create blockages that lead to the F75 error. These blockages can disrupt the flow of hot water and result in heating system inefficiencies.
  • Incorrect Pump Speed
  • Vaillant boiler pumpA faulty speed sensor can cause the pump to operate at the wrong speed, leading to the F75 code. Ensuring that the pump speed is correctly calibrated is vital for the smooth operation of your boiler.
The Vaillant boiler F75 fault is a common issue that can occur with several models.
For instance, Vaillant boilers, including the

EcoTec Vaillant boiler[EcoTec]
EcoTec Plus Vaillant boiler[EcoTec Plus]
EcoPro Vaillant boiler[EcoPro]

However, it appears when the boiler is unable to register a pressure change when the pump turns on. So, It is essential to contact a Gas Safe registered engineer without delay to diagnose and promptly repair Vaillant F75 error code on your boiler.

How to Diaognose the F75 Vaillant Fault?

  • Reset your Vaillant boiler by pressing the reset button with a flame icon.
  • Wait a few minutes for the boiler to restart.
  • Run a nearby hot tap and listen for the boiler to fire up and the heat pump to start working.
  • If the pump functions normally, it should produce a gentle humming sound and a slight vibration. If not, it may require repair.
  • If the pump operates normally, but the hot water supply cuts off suddenly, it may indicate a faulty pressure sensor, triggering the boiler F75 fault.
If you own a newer EcoTec Pro and are sure it is not affected by the manufacturing defect discovered in older models, there may be other possible causes for a faulty pressure sensor.

How to Identify ‘Faulty Pressure Sensor’?

pressure sensor in a Vaillant boiler
If you are experiencing hot water loss and seeing the Vaillant F75 code on your boiler, even though the pump seems to be working fine, the most likely culprit is a faulty pressure sensor.

One major factor contributing to sensor malfunctions is the accumulation of debris over time, primarily due to water presence. The circulating water in your central heating system can easily clog up the pressure sensor in your boiler. That's why it is highly recommended to perform a power flush during the installation of a new boiler.

When there is debris on the sensor, it cannot detect pressure changes properly, which can cause the pump and boiler to malfunction. While cleaning the pressure sensor may seem like a logical solution, it's often more cost-effective to replace it entirely.

Residents in hard water areas are prone to limescale accumulation.

How to Fix the F75 Error?

There are a few steps you can take to troubleshoot the F75 Vaillant fault.
Inside of a Vaillant boiler
  1. First, check the connected pipes for any visible signs of damage or leaks.
  2. Next, try resetting your boiler by turning it off and on again. This can sometimes resolve the error code if it was triggered by a temporary issue. If the F75 fault persists, you may need to call a qualified heating engineer to diagnose and fix the problem.
  3. Unfortunately, the Vaillant F75 error cannot be fixed using DIY methods.
  4. To fix the broken pump, you need to consult a qualified gas-safe engineer who will replace it with a new one.
  5. If you encounter a faulty pressure sensor that needs cleaning, you also need the expertise of a gas-safe engineer.
However, it's important to consider that cleaning is not usually recommended because of the high labour costs involved. It is often more cost-effective to simply replace the pressure sensor with a new one.

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How Can You Avoid the F75 Vaillant Fault Code From Happening Again?

To prevent the Vaillant F75 error code from appearing again, there are a few steps you can take. These include:
Ensuring Regular Maintenance
Having your boiler serviced annually by a qualified engineer can help identify and prevent any potential issues before they escalate.
Keeping An Eye On The Pressure
Check your boiler's pressure regularly, especially during the colder months when it is more likely to drop. If it consistently falls below the recommended level, it can strain the boiler and potentially trigger an error code.
Ensuring Annual Boiler Service
While there is no exact way to prevent the F75 fault from occurring, there are a few steps you can take to minimise the chances of it happening. Regular maintenance and an annual boiler service by a qualified engineer can help catch any potential issues before they escalate into an error code.
performing a central heating  powerflush Another effective method to safeguard your boiler is by performing a powerflush. This process eliminates magnetite, a common culprit behind pressure sensor failures. This will decrease the chances of encountering a Vaillant F75 error code in the future.
Properly Bleeding Radiators
If you need to bleed your radiators frequently, it simply means that there can be an underlying concern that needs to be addressed.

However, this F75 fault code is a common and frustrating issue for homeowners. By understanding its causes and taking preventative measures, you can ensure your boiler runs smoothly and avoid future disruptions. If you are unsure or uncomfortable dealing with the issue yourself, it is always best to seek professional help from a qualified engineer. Stay proactive and keep your heating system well-maintained to prevent the Vaillant F75 error code from occurring in the first place.

Call Serviceteam Boiler Professionals

As an accredited service provider for Vaillant boilers, Serviceteam is committed to taking the requisite measures and delivering expert repairs to address the matter effectively.

Our professional heating engineers are readily available to help you 24/7 with boiler emergencies, repairs, and boiler installations in London.

Happy heating!


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