F73
FAULT CODE
Glow-worm
Water Pressure Sensor Signal Too Low
High Severity
Engineer Required
The pressure sensor is reading below its expected range. Could mean genuinely very low pressure or a faulty sensor.
Step-by-Step Fix Guide
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Step 1
Check the pressure gauge on the boiler
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Step 2 Engineer only
If pressure is correct but F73 persists, the pressure sensor needs replacing — call a Gas Safe engineer
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.