E28
FAULT CODE
Main Heating
Frozen Condensate / Flue Thermistor Fault
Medium Severity
DIY Check Possible
In cold weather, E28 on Main Heating boilers indicates a frozen condensate pipe. In warmer conditions, may indicate a flue thermistor fault.
Cold Weather Note
E28 in winter almost always means a frozen condensate pipe on Main Heating boilers.
Step-by-Step Fix Guide
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Step 1
In cold weather, thaw the condensate pipe with warm water
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Step 2
Reset the boiler
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Step 3
If fault persists in warm weather, call a Gas Safe engineer to check the flue thermistor
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.