F21
FAULT CODE
Glow-worm
Flow Rate Sensor Fault
Medium Severity
Engineer Required
The water flow rate sensor is giving incorrect readings.
Step-by-Step Fix Guide
-
Step 1 Engineer only
A Gas Safe engineer should test the flow sensor
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.