F5
FAULT CODE
Saunier Duval
Overheat Fault
High Severity
Engineer Required
The overheat safety thermostat has operated on the boiler. Usually caused by poor circulation, low water pressure, or air in the system.
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
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Step 3
Bleed radiators
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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.