F23
FAULT CODE
Heatline
Flow/Return Temperature Difference Too High
Medium Severity
Engineer Required
The temperature difference between flow and return is excessive, indicating circulation problems.
Step-by-Step Fix Guide
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Step 1
Check system pressure and bleed radiators
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Step 2
Ensure all valves are fully open
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Step 3 Engineer only
Call a Gas Safe engineer to check the pump speed settings
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.