Common Vaillant Boiler Fault Codes and What They Mean
If your Vaillant boiler in Wokingham is showing a fault code or refusing to ignite, you’re not alone. Whether you live in Woosehill, Finchampstead, or Lower Earley, many homeowners rely on Vaillant systems — and like all boilers, they can run into problems.
At Thermo-Tec Plumbing & Heating, we help local residents quickly diagnose and repair boiler faults. Here’s your go-to guide to Vaillant boiler error codes, how to reset the system, and when to call in a qualified Gas Safe engineer.
Common Vaillant Boiler Fault Codes
These are the most frequently encountered Vaillant error codes across Wokingham homes:
F28 – Boiler Fails to Ignite
What it means: The boiler couldn’t establish a flame.
Likely causes:
Frozen condensate pipe (very common in winter)
Gas supply issues
Faulty ignition electrode
Quick fix:
Ensure the gas supply is on
If it's freezing outside, thaw the condensate pipe
Press the reset button once
Still showing F28? It may be time to give us a call — especially if it recurs.
F29 – Flame Lost During Operation
What it means: The flame went out during heating.
Causes:
Flue blockage or draught
Low gas pressure
Faulty sensor or gas valve
Fix tip: Try a reset — but if the issue persists, it may need a deeper inspection.
F22 – Low Water Pressure
What it means: Pressure in your heating system is too low to operate safely.
DIY fix:
Check the pressure gauge (should read between 1.0–1.5 bar)
Use the filling loop to repressurise the system
Reset the boiler
If your Vaillant boiler in Wokingham keeps losing pressure, you might have a leak or a faulty expansion vessel.
How to Reset Your Vaillant Boiler
Most Vaillant combi and system boilers have a simple reset procedure:
Locate the reset button or dial (usually with a circular arrow symbol)
Hold it down for 3–5 seconds
Wait for the boiler to restart
If the same error comes back repeatedly, avoid repeated resets — give us a call or book a repair with us
When to Call us your Local Gas Safe Engineer in Wokingham
If you're seeing recurring fault codes, unusual noises, smells, or a total system shutdown, it's time to call a qualified heating engineer.
At Thermo-Tec Plumbing & Heating, we’re Gas Safe registered and experienced with Vaillant fault codes. We cover Wokingham, Lower Earley, Woosehill, and surrounding villages.
Need a Vaillant Boiler Repair in Wokingham?
If your Vaillant boiler is showing a fault code or refusing to fire up, we’re here to help.
Call Thermo-Tec today on 07850116944 for Vaillant boiler repairs in Wokingham and surrounding areas.
Vaillant Boiler Fault FAQs
Q: What’s the difference between F28 and F29?
A: F28 means the boiler failed to ignite; F29 means it started, but the flame went out. Both relate to ignition/gas issues.
Q: Do you cover villages around Wokingham too?
A: Yes — we regularly attend properties in Arborfield, Winnersh, and Barkham.
Q: Can I fix F22 low pressure myself?
A: You can repressurise the boiler using the filling loop. If it happens often, there may be a leak or faulty part that needs professional attention.