Glow-worm 23c Fault codes & diagnostics

1 fault code with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.

Combi Natural Gas 23 kW 2000-2003 Discontinued
GC Number 47-047-18
Download the Glow-worm 23c manual The official installation & service manual (PDF) — the exact document these fault codes were verified against. PDF

This boiler uses LED flash patterns

Count the flashes in one repeating group before the pause. That number is your fault code. Do not reset until you have noted it. How to read fault codes →

Which version do you have?

The GC number on your boiler's data badge identifies the exact appliance and production years, as recorded in the UK Product Characteristics Database.

GC number Appliance (register name) Produced
47-047-18 23c 2000–2003

Appliance names and production years are taken from the UK Product Characteristics Database (the SAP/SEDBUK register). Where a GC number is also printed in this model's own manufacturer manual, both sources were checked to agree.

All 1 documented codes

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Red flashing light (Gas)

Your boiler has stopped working because it is not receiving a reliable supply of gas.

Emergency Engineer only £120-250

Parts commonly replaced

  • Gas valve
  • Gas meter regulator
  • Ignition lead