What does the Baxi 128 error code mean?
On the Baxi 800, Platinum and Duo-Tec ranges, fault 128 means the boiler's flame was lost mid-operation. It's usually a gas-supply, flue or flame-sensing issue and needs an engineer.
What causes the Baxi 128 fault?
The 128 error on a Baxi boiler is most commonly triggered by:
- Gas-supply interruption or fluctuation
- A blocked or partially blocked flue
- A worn flame-detection electrode or lead
- A failing gas valve
How to fix the Baxi 128 boiler fault
Follow these steps. If the code returns after you have completed them, stop and call a Gas Safe engineer.
- 1.Check other gas appliances are working.
- 2.Reset the boiler once; if 128 returns, don't keep retrying.
- 3.Book a Gas Safe engineer to test the flame electrode, flue and gas valve.
Frequently asked questions about the Baxi 128
What does fault 128 mean on a Baxi boiler?
128 means the flame went out while the boiler was running. The likely causes are a gas-supply dip, flue blockage or a faulty flame electrode, and it needs a Gas Safe engineer.
Is Baxi fault 128 dangerous?
Not on its own — it's a protective lockout. Don't keep resetting it; check the gas supply and arrange an engineer to investigate the flame and flue.