Vaillant F75 Fault Code


The Vaillant F75 fault number indicates the boiler’s water pressure is too high or too low. It means that there is less or no water flow in the heating system, which could cause the boiler to turn off as a safety measure.

Common reasons for the Vaillant F75 fault code include:

  1. Water Leak: There might be a leak somewhere in the heating system, causing the water pressure to drop.
  2. Pressure Sensor Issue: The pressure sensor that detects the water pressure may be faulty or malfunctioning.
  3. Expansion Vessel: The expansion vessel, which helps regulate water pressure changes, could be faulty.
  4. Blocked Pipework: Blocked or restricted pipework can also lead to low water pressure in the system.

How to Fix Vaillant F75 Fault Code?

To fix the F75 fault code, you will need to identify the underlying cause of the problem. If the pump is faulty, it will need to be replaced. If the pressure sensor is clogged, it will need to be cleaned or replaced. If the water pressure is low, you will need to add water to the boiler.

Here are the steps on how to fix the F75 fault code:

  1. Find the reset button on your boiler. It is usually located near the display panel.
  2. Press and hold the reset button for 10 seconds.
  3. Check the boiler display to see if the F75 fault code is still displayed. If it is, proceed to the next step.
  4. Check the water pressure in the boiler. The water pressure should be between 1 and 2 bar. If the water pressure is low, add water to the boiler until it reaches the correct level.
  5. If the water pressure is correct and the F75 fault code is still displayed, call a qualified plumber or heating engineer to diagnose and repair the problem.

Here are some additional things to keep in mind when trying to fix the F75 fault code:

  • Do not operate the boiler if it is displaying the F75 fault code. This could damage the boiler and void your warranty.
  • If you are not comfortable working on your boiler, call a qualified plumber or heating engineer.


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