BoilerFaultCodesBaxi E4 Fault Code
The Baxi E4 fault code means: your boiler is struggling to light and stay on, which can sometimes be caused by trapped air in your heating system preventing the water from flowing correctly.. It appears on 24 Baxi models in our database.
Technical description: Ignition failure – try bleeding your radiators
What causes the Baxi E4 fault?
This fault occurs when the boiler tries to light the flame but fails to detect one, causing the system to shut down for safety. The most common reason is that the spark isn't strong enough to ignite the gas, or the sensor that monitors the flame has become dirty or worn out. It can also be triggered if air is trapped in the system, which disturbs the internal pressure and prevents the boiler from operating correctly.
This fault often appears after the summer break when the boiler is switched back on for the first time or after the system has been drained for radiator maintenance.
DIY fix possible
Turn off the boiler and wait for the radiators to cool downUse a radiator key to bleed any air from all radiators in the houseCheck the boiler pressure gauge and top it up to 1.5 bar if it has droppedPress the 'Reset' button on the boiler control panel
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Baxi models that show the E4 fault code
Click a model for the full fault code list and model-specific repair notes.
- 400 Combi (range) Repair: £100-280
- 800 Repair: £100-280
- 80e Repair: £100-280
- Assure Repair: £100-280
- Avanta Repair: £90-280
- Bermuda Repair: £100-280
- Duo-tec Combi Repair: £100-300
- Eco Compact Repair: £90-180
- Eco Elite Repair: £100-280
- EP Repair: £100-280
- Netaheat Repair: £60-180
- Performa Repair: £120-300
- Profile Repair: £80-250
- Profile Prima Repair: £80-250
- Statesman Repair: £60-180
- Suprima 100 Repair: £120-280
- Suprima 115 Repair: £100-280
- Suprima 30 Repair: £80-250
- Suprima 40 Repair: £120-300
- Suprima 50 Repair: £90-280
- Suprima 60 Repair: £90-250
- Suprima 70 Repair: £120-350
- Suprima 80 Repair: £120-350
- Titanium Repair: £80-250
Source
Baxi E4 fault code information on this page is sourced and cross-checked against the official Baxi service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026