Baxi E103 means the Safety Assist battery is exhausted. That is the exact description in Baxi’s current public error-code table. It does not mean the household batteries in a room thermostat, a wireless controller or a carbon-monoxide alarm need changing.
The Safety Assist system is part of the appliance arrangement covered by Baxi’s technical documentation. Keep the boiler casing closed, confirm your exact model and arrange a repair if a model-approved reset does not clear the code.
What does Baxi fault code E103 mean?
Baxi lists E103 as “Safety Assist battery is exhausted”. In plain English, the boiler has detected that the battery associated with that safety function can no longer provide the expected condition.
The manufacturer’s public table does not instruct homeowners to locate or replace it. Do not confuse it with batteries in external heating controls. Opening the boiler to reach internal parts is not a homeowner job.
Which Baxi boilers use E103?
E103 appears in Baxi’s error-code group covering ranges including Platinum Compact, Duo-tec Compact, Megaflo Compact, 600, 800, Assure, Platinum, Platinum+, Duo-tec, Megaflo and EcoBlue models, alongside related Main and Potterton appliances.
Exact use can depend on model and configuration. Check the full model name and use the matching Baxi user guide. If the display shows another code before or after E103, record the complete sequence.
Safe checks you can make
- Confirm the display really reads E103, not a similar code.
- Note whether heating, hot water or both have stopped.
- Check the boiler has stable power and that no property-wide power cut has occurred.
- Photograph the display and record the complete model name.
- Try one reset only if the correct user guide permits it.
Baxi boilers use different reset controls. Follow the exact model guide. If E103 stays on the display or returns, stop resetting and arrange professional attention.
Can I change the battery myself?
Not on the basis of the E103 message. Baxi’s homeowner information does not present the Safety Assist battery as a user-replaceable item. Do not remove the case, search for a battery, disconnect wiring or fit a substitute.
An engineer can confirm model applicability, inspect the safety system correctly and use an approved replacement where required.
Is E103 the same as a thermostat low-battery warning?
No. A wireless thermostat may have its own battery symbol or message, but E103 is a boiler error code with a specific manufacturer definition. Changing room-control batteries may be sensible when that control separately reports low power, but it should not be assumed to repair E103.
Is the boiler safe to keep resetting?
No. The boiler has reported an issue connected with a named safety function. One permitted reset can help confirm whether the code is temporary, but repeated resets do not restore an exhausted battery and should not be used to force continued operation.
If you smell gas, suspect a leak, or a carbon-monoxide alarm sounds, do not reset the boiler. Avoid electrical switches, leave the property and call the National Gas Emergency Service on 0800 111 999 from a safe place.
Does E103 mean a new boiler?
No. E103 identifies a specific fault condition, not the overall state of the appliance. The correct repair and its value depend on the exact model, confirmed fault, age, condition and parts availability.
Get your Baxi E103 fault fixed
Book Incredaboil’s fixed-price boiler repair for a clear visit aimed at getting your heating and hot water working properly again.
Baxi E103: the short answer
E103 means the Safety Assist battery is exhausted. It is not an instruction to change external thermostat batteries. Keep the casing closed, use only the permitted reset and book a Gas Safe registered repair if the code remains.