F25
FAULT CODE
Saunier Duval
Flow Temperature Rising Too Fast
High Severity
Engineer Required
The flow temperature is rising at an unsafe rate — possible pump failure or severe airlock.
Step-by-Step Fix Guide
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Step 1
Check system pressure and bleed radiators
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Step 2
Reset once
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Step 3 Engineer only
If fault persists, call a Gas Safe engineer to check the pump
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.