Vaillant F32 Fault Code - Likely Causes and Possible Fixes

May 19, 2021

Vaillant F32 Fault Code - Likely causes and possible fixes

A perceived lack of airflow causes the Vaillant F32 fault code. Various faults can cause an F32 error, including a block in the flue pipe, a leak or wet sensors, a faulty fan, or a communication failure between the fan and the PCB.

What is the Vaillant f32 fault code?


The Vaillant Ecotec boiler is very clever. To make sure the boiler doesn’t fire if the fan isn’t running sufficiently,

it has a sensor attached that measures the speed of the fan.

 If the fan fails to start or isn’t running fast enough, the boiler will not light.

Two things can happen when the boiler fan is defective:

  • 1) The POC   ( products of combustion ) will not be vented outside via the flue duct, and 
  • 2) Fresh air for combustion will not be pulled into the boiler.


Fossil fuels such as coal, natural gas, or even wood require an adequate supply of oxygen when burned. If they do not get a sufficient amount of air, they produce high levels of CO (Carbon Monoxide ).

To prevent this, potentially fatal, scenario from developing in your home, Vaillant boilers produce the F32 fault code when poor airflow is detected.


What can cause the Vaillant F32 fault Code?

As we know, the Vaillant F32 fault code points to the fan. Unfortunately, onboard boiler diagnostics are not 100% accurate, and there could be a few reasons why your Vaillant boiler will produce the F32 fault code.

The main reasons your Vaillant will show an F32 fault code are:

  •  If the fan doesn’t reach a suitable speed. The fan inside your Vaillant boiler is robust and durable. However, the bearings can loosen over time, causing the propeller to slow or stop spinning altogether, and your boiler will display an F32 fault code.
  • If the wiring harness that relays information between the PCB and fan isn’t transferring the information or doesn’t have a good connection. Some reasons the wiring harness fails are due to it melting after poor maintenance, rodent infestation inside the boiler, and general failure.  
  • If the PCB isn’t reading the information correctly or isn’t sending power to the fan. The PCB can fail for many reasons, but it’s usually caused by moisture inside the boiler case from a small leak. If the PCB fails, you might get an intermittent F62 fault code and the F32 code.
  • If the flue is blocked or obstructed and your boiler isn’t pulling fresh air in or venting the combustion products sufficiently. Boiler flues are usually protected to stop blockages, and adequate boiler servicing should prevent anything from building up inside your boiler to restrict the airflow.


Can I Fix The The Vaillant F32 Fault Code?

You can try to reset the F32 fault on your Vaillant boiler. The Ecotec will occasionally suffer from nuisance lockouts which means the boiler isn’t broken and might reset. However, it will usually mean a fault is developing, and further diagnostics is advised.

Unfortunately, If the boiler does not reset, you’ll need to call a Gas Safe registered boiler repair engineer as the Vaillant Ecotec F32 fault will almost certainly be due to a fault within the boiler casing. 

The fan is also connected to the gas valve and replacing it will involve opening the gas supply. 

A trained Gas Safe Registered boiler repair engineer is the only person who can repair the boiler.


How Much Should The Vaillant F32 Fault Cost To Repair?

The cost to repair the F32 fault will depend on lots of things, where you live and when you need the repair will have a direct impact on the price.

Also, if the harness is defective, it will be cheaper to repair than if the PCB is faulty.

We’ve heard horror stories of people being convinced to replace boilers that are less than ten years old because they have an F32 fault code, the Vaillant Ecotec F32 fault will not cost anything near the price of a new boiler.

An experienced boiler repair engineer should be able to diagnose the problem and repair the fault in a maximum of two hours with parts costing anything from £50 - £300,  so while it’s not cheap, it’s certainly no reason to be conned into a new boiler installation.

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