BoilerFaultCodesPotterton TTB constant trip Fault Code
Also written as TTBCONSTANTTRIP — same fault.
The Potterton TTB constant trip fault code means: your boiler is automatically shutting down because it has detected dangerous exhaust fumes backing up into your home instead of escaping safely through the chimney.. It appears on 1 Potterton model in our database.
Technical description: If the unit continues to trip then the flue should be checked for spillage.
What causes the Potterton TTB constant trip fault?
This fault occurs when a safety sensor detects that the hot exhaust gases are not rising correctly through the chimney and are instead spilling back into the room. The most common reason is a blockage in the flue, a damaged chimney liner, or poor atmospheric conditions that prevent the natural pull of the chimney. Because these fumes contain carbon monoxide, the boiler shuts down immediately to prevent a dangerous build-up in your home.
This issue is more common during particularly windy weather or high-pressure summer days when atmospheric conditions can push air back down the chimney, causing a 'down-draught'.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Gas Safe Register →Potterton models that show the TTB constant trip fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Potterton TTB constant trip 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