Warmworld HE 70/80 Fault codes & diagnostics

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

Regular Natural Gas 70 kW 1993 onwards Discontinued
GC Number 41-555-04
Download the Warmworld HE 70/80 manual The official installation & service manual (PDF) — the exact document these fault codes were verified against. PDF

The fault code is already on your display

Note it down before pressing reset — resetting clears the code immediately. How to read fault codes →

Versions & GC numbers

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
41-555-04 Warmworld HE 30 1993–present
Fault codes

All 1 documented codes

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LOCKOUT

Your boiler has shut down because its exhaust system has become too hot, which is a safety feature to prevent damage or dangerous fumes.

High Engineer only £120-250

Parts commonly replaced

  • Flue thermostat
  • Main heat exchanger
  • Burner gasket

Related codes

Full explanation for LOCKOUT
Status & diagnostic codes

4 operating states & engineer diagnostics

Not faults — these are normal operating states. Tap to expand.

30 Diagnostic Your boiler is struggling to breathe properly because the airflow inside the unit is blocked or restricted. 40 Diagnostic Your boiler has detected an issue with the air intake or exhaust flue system, preventing it from operating safely. 50 Diagnostic Your boiler has detected an issue with the air intake or exhaust flue system, preventing it from operating safely. 80 Diagnostic Your boiler is detecting an issue with the air intake or exhaust ventilation system that prevents it from burning fuel safely.