Vaillant Combi Boiler F.28 Error
Ignition failure — no flame
The boiler could not detect a flame after several ignition attempts and locked out.
What is error F.28?
On Vaillant Combi Boiler units, code F.28 means ignition failure — no flame. The boiler could not detect a flame after several ignition attempts and locked out.
Likely causes
- Gas valve closed or gas supply interrupted
- Dirty ignition / ionisation electrode
- Gas valve, control board or earthing fault
Safe steps you can take
- Check that the meter and boiler gas valves are open.
- Check whether other gas appliances such as the hob work.
- Reset the boiler once. If the fault returns, switch off and call a technician.
If you smell gas, do not touch electrical switches, close the valve, ventilate and call the gas emergency line (187 in Türkiye).
Video guide
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Watch on YouTubeFrequently asked questions
Is error F.28 dangerous?
Gas, water and electricity are involved, so take care. Only do the safe steps on this page and don't touch internal parts.
Is a reset enough?
One reset clears temporary causes. If the code comes back, the real cause remains — don't keep resetting.
How much does the repair cost?
It depends on the part. After diagnosis the service sends the price to your tracking link; nothing is done without your approval.
Is the repair guaranteed?
Services on the platform write the warranty for parts and labour on the service form, which is sent to you as a PDF.
Sources: tesisat.org — Kombi arıza kodları . Code meanings can vary by model; check your user manual.