How much does it cost to fix Baxi error code E135?

Typical repair cost for the Baxi E135 fault is £180-350 including labour.

E135 High

Baxi E135 Fault Code

Q: What does the Baxi E135 fault code mean?

Your boiler has lost its connection to the gas supply due to an internal electronic communication failure, meaning it cannot ignite to provide heat or hot water.

The Baxi E135 fault code means: your boiler has lost its connection to the gas supply due to an internal electronic communication failure, meaning it cannot ignite to provide heat or hot water.. It appears on 24 Baxi models in our database.

Technical description: Interruption of gas supply (internal error)

What causes the Baxi E135 fault?

This fault occurs when the boiler's main control board loses the ability to communicate with the gas valve, preventing the system from releasing fuel for ignition. The most common reason is a malfunctioning printed circuit board (PCB) or a loose connection in the internal wiring harness. In some cases, the gas valve itself may have developed an electrical fault that keeps it from responding to the boiler's commands.

Typical repair cost £180-350 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

Find a Gas Safe engineer

Search the official register for a qualified engineer in your area.

Gas Safe Register →

Baxi models that show the E135 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Baxi E135 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