How F28 shows up
- No heating and no hot water
- The boiler tries to light several times then shuts down
- Code F28 stays on display after a reset
- Repeated clicking, without the burner lighting
- The fault comes back systematically after a few hours
What error code F28 means
- Ignition failure — the boiler tried to light the burner three times, then cut off the gas as a safety measure.
- Gas supply cut — closed valve, meter switched off, or a network outage.
- Dirty ignition electrode — the spark no longer forms properly. The most common cause after several years without servicing.
- Faulty ionisation electrode — the flame lights, but the boiler fails to detect it.
- Blocked flue — a bird's nest, leaves or ice in the duct.
What you can safely check yourself
Is gas reaching the boiler?
Check that another gas appliance in the home is working, and that the boiler's gas valve is fully open.
Reset once
Press the reset button (often marked with a crossed-out flame or 'reset'). If the code returns, don't keep trying.
Code still there? Call a professional
An F28 that returns after a reset almost always comes from the electrode or the flue — these need a licensed technician.
Which brands does this code apply to?
This code is used as-is on Vaillant and Bulex boilers, two brands that share the same technical platform. On Junkers, Viessmann, Atlantic and Remeha boilers, an equivalent fault shows under a different code — our technician identifies the fault on site, whatever the brand.
A clear price, no surprises
A fixed 35 € call-out fee in Brussels, Wallonia and Flanders. The repair price is given to you before any work starts. Free, no-obligation quote on 0488 02 77 07.