How much does it cost to fix Potterton error code Red LED (TTB)?

Typical repair cost for the Potterton Red LED (TTB) fault is £150-300 including labour.

Red LED (TTB) Emergency

Potterton Red LED (TTB) Fault Code

Q: What does the Potterton Red LED (TTB) fault code mean?

Your boiler has detected that fumes are not escaping properly through the flue, so it has shut itself down automatically to keep you safe from harmful exhaust gases.

Also written as REDLEDTTB — same fault.

The Potterton Red LED (TTB) fault code means: your boiler has detected that fumes are not escaping properly through the flue, so it has shut itself down automatically to keep you safe from harmful exhaust gases.. It appears on 2 Potterton models in our database.

Technical description: The red LED will be illuminated in the case of flue blockage (CFL Only) when the Products Discharge Safety Device (TTB) operates and the boiler goes to lockout.

Typical repair cost £150-300 (including labour)

Engineer required

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

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Potterton models that show the Red LED (TTB) fault code

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

Source

Potterton Red LED (TTB) fault code information on this page is sourced and cross-checked against the official Potterton service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026