47
FAULT CODE
Alpha
Reduced Burner Output — Flue Thermostat Active
Medium Severity
Engineer Required
The flue thermostat has sensed high flue gas temperature and reduced the burner output as protection. If the temperature continues to rise, the boiler will lockout with code 3.
Step-by-Step Fix Guide
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Step 1
Check for air in the heat exchanger by bleeding radiators
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Step 2
Check for restricted primary flow
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Step 3 Engineer only
Call a Gas Safe engineer if the reduced output condition persists
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.