What does Vaillant F28 mean?

Ignition failure — the boiler couldn't establish a flame at start-up.

How do I fix Vaillant F28?

Try first: Check other gas appliances work; Check the condensate pipe isn't frozen; Press reset once. If that doesn't clear it, the likely part is Ignition electrode set.

Vaillant F28 Fault — What It Means & Fix Cost

⚠ This is the likely cause from the code — a Gas Safe registered engineer confirms it on site. If you can smell gas, stop and ring 0800 111 999.

✅ Try these first — they're free

Often clears it without a callout:

Check other gas appliances work
Check the condensate pipe isn't frozen
Press reset once

🔧 If that doesn't fix it

The likely cause is one of these — the engineer confirms which:

Gas supply issue
Ignition electrodes
Gas valve
Blocked condensate trap

Most likely part: Ignition electrode set

⚠ Worth knowing

A blocked condensate trap often causes F28 in winter and is quick to clear before condemning the gas valve

Fixed repair price

£190

Part + labour, no surprise callout fee. You only pay if you go ahead.

Book a Gas Safe engineer

You pick from the 3 nearest vetted engineers. Your choice gets first refusal; if they don't take it within a few hours it moves to the next nearest automatically — and we keep you posted.

Other Vaillant fault codes

Vaillant F22Low water pressure / dry-fire protection — not enough water …Vaillant F75Pressure sensor or pump fault — the boiler didn't see a pres…

Vaillant F28 — what it means

✅ Try these first — they're free

🔧 If that doesn't fix it

⚠ Worth knowing

Other Vaillant fault codes