Brand hub
Vaillant Fault Codes
Check Vaillant boiler fault codes and understand which steps are safe for homeowners and which need an engineer. Use this hub to move into the right appliance section, then open the exact code page for the documented meaning, evidence limits and safe next steps.
Definitions can vary by model and region. Some codes remain unconfirmed; check the complete display, exact model and the page's sources before taking action.
Appliance hubs
1
Fault code pages
28
Guides linked in
3
Appliance types
Appliance codes across brands
Selected code pages
F22
Low water pressure. Applies only within the model and regional limits on the code page.
F28
No flame established during ignition. Applies only within the model and regional limits on the code page.
F29
Flame lost during operation and re-ignition unsuccessful. Applies only within the model and regional limits on the code page.
F25
Flue-gas temperature too high. Applies only within the model and regional limits on the code page.
F24
Boiler temperature rising too quickly. Applies only within the model and regional limits on the code page.
F32
Fan fault. Applies only within the model and regional limits on the code page.
Code categories in this library
Counts refer to published code pages, not how often an appliance develops a fault.
sensor (10)
ignition (4)
PCB and control (4)
circulation (3)
fan and flue (2)
overheat (2)
More code pages
F22 for Boiler
Low water pressure
F23 for Boiler
Excessive flow-to-return temperature difference
F24 for Boiler
Boiler temperature rising too quickly
F25 for Boiler
Flue-gas temperature too high
F27 for Boiler
Flame signal detected with the burner off
F28 for Boiler
No flame established during ignition
F29 for Boiler
Flame lost during operation and re-ignition unsuccessful
F32 for Boiler
Fan fault
F75 for Boiler
Insufficient pressure change when the pump starts
F00 for Boiler
Interrupted flow-temperature sensor circuit
F01 for Boiler
Interrupted return-temperature sensor circuit
F10 for Boiler
Short circuit at the flow-temperature sensor
Related guides
Practical background guides connected to this brand's fault-code pages.
Boiler Fault Codes: When to Stop and Call a Professional
First separate an emergency from a routine fault. A code needs the exact model and full display; it cannot by itself establish a safe reset or identify a part to replace.
When to Call an Appliance Engineer
Use the exact manual for permitted owner checks. Recurring faults, unsafe symptoms and work inside the appliance need appropriate professional help; emergencies need immediate action.
Why Your Boiler Keeps Losing Pressure
Use the pressure target and filling instructions for your exact boiler and installation. Repeated pressure loss needs investigation; a low reading alone does not identify a failed component.