F77
FAULT CODE
Glow-worm
Condensate System Fault / Pump Fault
Medium Severity
Engineer Required
A fault with the condensate system or pump. On models with a condensate pump, this may indicate the pump has failed or its float switch has stuck.
Cold Weather Note
In winter, check for a frozen condensate pipe before assuming pump failure.
Step-by-Step Fix Guide
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Step 1
In winter, check the external condensate pipe for freezing first
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Step 2 Engineer only
If not frozen, a Gas Safe engineer should inspect the condensate pump (if fitted) and siphon
Gas Safe Reminder
Work on gas appliances must be carried out by a Gas Safe registered engineer. The steps above cover safe checks a homeowner can perform - any internal component replacement requires a qualified professional. If in doubt, always call an engineer.