Verified boiler fault code

Glow-worm F9 Fault Code (Ultracom hxi)

Water pressure sensor fault, blocked flow filter or pump fault.

Safety disclaimer

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Fault code summary

Manufacturer
Glow-worm
Fault code
F9
Fault type
Pressure sensor, Circulation, Pump
Severity
Not specified
Reset
Not specified
Applicable models
Ultracom hxi

Quick answer

Water pressure sensor fault, blocked flow filter or pump fault.

What does this fault code mean?

Water pressure sensor fault, blocked flow filter or pump fault.

Common causes

This information was not provided in the verified manufacturer source.

Symptoms

This information was not provided in the verified manufacturer source.

What can the homeowner safely check?

This information was not provided in the verified manufacturer source.

Boiler reset information

Reset information was not provided in the verified manufacturer source. Do not repeatedly reset an unresolved fault.

When should I call an engineer?

Contact a suitably qualified heating engineer when the fault persists, the boiler locks out, or the manufacturer instructions do not resolve it. For gas appliance work in the UK, use a Gas Safe registered engineer.

Engineer diagnosis

Engineer diagnosis information was not provided in the verified manufacturer source. A qualified engineer should diagnose the appliance safely.

Applicable boiler models

Related fault codes

Manufacturer documentation

Fault finding codes for the Ultracom hxi range

F9 | Water pressure sensor fault, blocked flow filter or pump fault

Last verified

2026-09-12

Frequently asked questions

What does Glow-worm F9 mean?

Water pressure sensor fault, blocked flow filter or pump fault.