BoilerFaultCodesIdeal Blocked Flue/Condensate Fault Code
Also written as BLOCKEDFLUECONDENSATE — same fault.
The Ideal Blocked Flue/Condensate fault code means: your boiler is unable to get rid of waste gases or waste water safely, which has caused it to shut down for protection.. It appears on 5 Ideal models in our database.
Technical description: 1 Check if condensate pipe blocked/frozen 2 Check if flue blocked 3 If fault persists, contact installer
What causes the Ideal Blocked Flue/Condensate fault?
This fault occurs when the boiler's sensors detect a blockage that prevents the safe removal of exhaust gases or waste water. The most common reason is a buildup of debris in the condensate trap or a physical obstruction in the external flue pipe. If these paths are blocked, the boiler automatically shuts down to prevent dangerous fumes from entering your home or water from backing up into the internal components.
This fault is significantly more common during freezing winter temperatures, as the external condensate pipe can freeze and prevent waste water from draining away.
DIY fix possible
Check the white plastic pipe outside for ice and pour warm water over it if frozenEnsure the external flue terminal is not obstructed by leaves, nests, or debrisCheck that the internal condensate trap isn't visibly full of sludge
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Gas Safe Register →Ideal models that show the Blocked Flue/Condensate fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ideal Blocked Flue/Condensate fault code information on this page is sourced and cross-checked against the official Ideal service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026