E5
FAULT CODE
Biasi
NTC Sensor Fault
Medium Severity
Engineer Required
A temperature sensor (NTC thermistor) has a fault — either the flow or return sensor.
Step-by-Step Fix Guide
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Step 1 Engineer only
Call a Gas Safe engineer to identify which sensor has faulted and replace it
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.