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Baxi boiler fault codes
Common Baxi codes for Baxi 200, 400, 600, 800 and Assure boilers, what they mean and what to do.
Baxi boilers show an E code on the display, such as E133. Some older models flash a light instead. These are the ones we deal with most.
| Code | What it means | What to do |
|---|---|---|
| E133 | Gas supply interrupted, or the flame failed to light. | Check other gas appliances and your meter. In cold weather, check the condensate pipe. Reset once, then book a repair if it returns. Engineer needed if it returns |
| E118 / E119 | Water pressure too low (the number depends on the model). | Top up to about 1 to 1.5 bar using the filling loop. If it keeps dropping, book a repair. You may be able to fix this |
| E117 | Water pressure too high. | Usually over-filled or a faulty filling loop or expansion vessel. Book a repair visit. Engineer needed if it returns |
| E110 | Overheat. The safety thermostat has tripped. | Check the pressure and that radiators are warming. Reset once, then book a repair. Engineer needed if it returns |
| E125 | Circulation fault. Water is not moving through the boiler properly. | Often a pump fault, air or sludge. Bleed the radiators and check the pressure, then book a repair. Engineer needed if it returns |
| E160 | Fan fault. | Needs an engineer to check the fan. Engineer needed if it returns |
| E28 | Flue fault. | Do not keep resetting. An engineer needs to check the flue. Engineer needed if it returns |
| E20 | Heating temperature sensor fault. | Book a repair visit. Engineer needed if it returns |
Codes and their meanings can vary between models and software versions, so check your boiler’s manual too. Never open the boiler casing yourself.
How to top up the pressure
Low pressure is the most common cause of a Baxi lockout. With the boiler cold, open the filling loop valves slowly until the gauge reads about 1 to 1.5 bar, then close them fully. Your manual shows where the filling loop is on your model. Read our full guide.
When to book an engineer
- The same code comes back after one reset
- The pressure keeps dropping after you top it up
- You see a false flame, flue or gas valve code
- There is water leaking from the boiler
Baxi questions
What does E133 mean on a Baxi boiler?
Gas supply interrupted, or the flame failed to light. Check other gas appliances and your meter. In cold weather, check the condensate pipe. Reset once, then book a repair if it returns.
How do I reset a Baxi boiler?
Most models have a reset button or a dial position marked reset. Press or turn it once, and wait a few minutes for the boiler to try again. Check your manual for your model. If the code returns, do not keep resetting it.
Do you repair Baxi boilers?
Yes. Our Gas Safe engineers repair Baxi boilers across South London. A repair visit is £90 including the first hour.
Other makes: Vaillant, Worcester Bosch, Ideal.