The Vaillant Boiler F28 error is a common fault code indicating an ignition failure or flame detection issue within your boiler system. When this error occurs, your boiler will shut down as a safety precaution to prevent further damage or unsafe operation.

Contact Our Expert Engineers Today for Boiler Repairs

What Does the F28 Error Mean?

The F28 error code specifically signals that the boiler is unable to detect a flame during the ignition process. This can be caused by several factors, including:

• Faulty ignition electrodes or flame sensors that fail to detect the flame
• Issues with the gas supply, such as blockages or interruptions
• Malfunctioning gas valves preventing the flow of gas
• A problem with the air pressure switch, which affects combustion
• Dirty or clogged burner components

Common Causes of Vaillant Boiler F28

Ignition failure may result from routine wear and tear or lack of maintenance. Here are some common causes:

• Dirty Electrode or Flame Sensor: Over time, carbon deposits can build up, causing the sensor to misread the flame.
• Gas Supply Problems: If your gas supply is interrupted or the meter is off, ignition won’t be possible.
• Faulty Gas Valve: The valve may get stuck or fail to open properly, preventing gas from reaching the burner.
• Air Pressure Switch Fault: This safety switch ensures correct air flow for combustion; if it malfunctions, the boiler won't ignite.

How to Fix the Vaillant Boiler F28 Error

While some troubleshooting steps can be performed safely by homeowners, many require professional attention due to safety risks involved. Here’s what you can try:

• Reset Your Boiler: Often, pressing the reset button can clear temporary glitches. Refer to your manual for instructions.
• Check the Gas Supply: Ensure the gas is turned on and the meter is operational.
• Inspect Water Pressure: Low pressure can sometimes cause ignition issues. Normal pressure is usually between 1 and 1.5 bar.
• Look for Visible Damage: Check for any obvious signs of damage or wear around the boiler.

Important: If resetting and simple checks do not fix the problem, do NOT attempt to repair internal components yourself. Gas appliances require expert handling to avoid danger.

When to Call a Professional Engineer

If the F28 error persists after basic troubleshooting, or if you notice any of the following, it’s time to call a Gas Safe registered engineer immediately:

• A persistent error code that won’t clear
• Unusual smells (gas or burning)
• Repeated boiler lockouts
• Signs of water leakage or corrosion

Professional engineers can safely diagnose and repair ignition faults, replace faulty parts, and carry out routine maintenance to prevent future errors.

Preventing F28 Errors

Regular servicing and maintenance of your Vaillant boiler can help prevent F28 and other error codes. Annual servicing by a qualified engineer ensures:

• Clean and efficient burner and ignition components
• Safe and reliable operation
• Early detection of potential issues before they cause faults

Download Vaillant Boiler Manual

For detailed technical information and maintenance tips, you can download the official Vaillant Ecotec installation and servicing manual here (PDF).

FAQs About Vaillant Boiler F28 Error