What it means
Baxi's Assure Combi user guide lists 135 as an interruption of the gas supply (internal error).
What to check, in order
- Check the gas isolation tap
Make sure the gas tap to the boiler is open.
- Check the meter
On a prepayment meter, check there's credit left.
- Reset if the reset symbol shows
Baxi's guide says to press Reset if the reset symbol is lit. If a spanner symbol shows instead, the boiler can't be reset by you.
When to call a Gas Safe engineer
If the spanner symbol shows or the code keeps coming back, call a Gas Safe registered engineer.
Quick answers
What does the Baxi E135 fault code mean?
The boiler lost its gas supply, or found an internal fault, and stopped. Baxi's Assure Combi user guide lists 135 as an interruption of the gas supply (internal error).
Can I fix Baxi E135 myself?
Easy (about 10 minutes). Start with: check the gas isolation tap; check the meter; reset if the reset symbol shows. If the spanner symbol shows or the code keeps coming back, call a Gas Safe registered engineer.
Is Baxi E135 worth repairing?
Usually free. Often it's the gas supply or the meter. If not, an engineer needs to look inside.
Checked against
Last reviewed October 2026. Manufacturers update their pages, and your manual is the final word. Spotted a mistake? Email contact@appliance-error-codes.com.