Glow-worm F25 Fault Code (Ultracom hxi)

Safety disclaimer

Fault code summary

Manufacturer

Glow-worm

Fault code

F25

Fault type

Circulation, Pump

Severity

Not specified

Reset

Not specified

Applicable models

Ultracom hxi

Quick answer

Circulation fault.

What does this fault code mean?

Circulation 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

• Ultracom hxi

Related fault codes

• F1 — Ultracom hxi

  Ignition fault.

  Read fault code
• F22 — Ultracom hxi

  Low water pressure or ignition temperature rise too slow.

  Read fault code
• F3 — Ultracom hxi

  Fan unable to reach ignition speed.

  Read fault code
• F5 — Ultracom hxi

  Overheat fault.

  Read fault code
• F77 — Ultracom hxi

  Condensate pump error (optional).

  Read fault code
• F9 — Ultracom hxi

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

  Read fault code

Manufacturer documentation

F25 | Circulation fault

Last verified

2026-09-12

Frequently asked questions