BoilerFaultCodesGlow-worm Condensate Drain Blockage Fault Code
Also written as CONDENSATEDRAINBLOCKAGE — same fault.
The Glow-worm Condensate Drain Blockage fault code means: your boiler has stopped working because the waste water pipe that carries away moisture is blocked, often due to frozen debris inside the pipe outside your home.. It appears on 1 Glow-worm model in our database.
Technical description: As a safety feature the boiler will stop working if the condensate drain becomes blocked. During freezing conditions this may be due to the forming of ice in the condense drain external to the house.
DIY fix possible
Locate the plastic condensate pipe running outside from your boiler.Pour warm (not boiling) water slowly over the outside of the pipe to melt any ice blockage.Place a container underneath the end of the pipe to catch any water if it is frozen inside.Once the water flows freely, reset your boiler using the reset button on the front panel.
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Glow-worm models that show the Condensate Drain Blockage fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Glow-worm Condensate Drain Blockage fault code information on this page is sourced and cross-checked against the official Glow-worm service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026