BoilerFaultCodesGlow-worm F74 Fault Code
The Glow-worm F74 fault code means: your boiler is having trouble measuring how much water is inside the system, which is causing it to stop running for safety.. It appears on 8 Glow-worm models in our database.
Technical description: Water pressure sensor fault
What causes the Glow-worm F74 fault?
This fault occurs when the boiler's internal computer receives an incorrect or missing electrical signal from the water pressure sensor. The most common reason is that the sensor has become blocked with system debris or has suffered an electrical failure, preventing it from verifying that there is enough water to operate safely.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Glow-worm models that show the F74 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Glow-worm F74 fault code information on this page is sourced and cross-checked against the official Glow-worm service / installation manuals for each affected model.
- Glow-worm Betacom2 28 manual (PDF)
- Glow-worm Easicom 28 manual (PDF)
- Glow-worm Ultracom 2 35cxi manual (PDF)
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 31 August 2026