F20
FAULT CODE
Heatline
Overheat Fault
High Severity
Engineer Required
The boiler has overheated and the safety limiter has activated. Caused by poor circulation, low water pressure, or a failing pump.
Step-by-Step Fix Guide
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Step 1
Turn off and allow to cool for 30 minutes
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Step 2
Check system pressure and bleed radiators
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Step 3
Ensure all isolation valves are open
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Step 4
Reset once
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Step 5 Engineer only
Call a Gas Safe engineer if fault returns
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.