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Wolf Boiler Error Codes
Exact code meanings can vary slightly by production year and model generation. This page is for general reference — before opening up your boiler yourself, especially for anything involving gas or electrical safety, we recommend contacting our technicians.
Wolf CGB-2 / CGW-2 Boiler Error Codes
- 001: STB (safety temperature limiter) tripped — overheating, usually from insufficient circulation. Bleed the system and check the pump.
- 004: No flame detected (burner fault). Check gas supply, ignition and ionisation electrodes.
- 013: Flue gas temperature sensor fault.
- 022: Insufficient air — the fan doesn't reach the required speed.
- 040: Flow-monitoring fault — check water pressure.
Note: the exact code table can vary by model generation (the STB limiter needs a manual reset, it won't clear itself) — contact our technicians for an accurate diagnosis.
Wolf FGB / FGB-K Boiler Error Codes
- 001: STB / overheating.
- 004: No flame detected.
- 005: Flame loss during operation.
- 014: Storage (cylinder) sensor fault.
Note: contact our technicians for an accurate diagnosis.
Wolf CGU-2K / TGB-2 / MGK-2 Boiler Error Codes
- A01 / E14: Ignition failed / gas fault — no flame.
- A02 / E42: Overheating detected / flue gas temperature too high.
- A04: Gas pressure problem — check the gas valve assembly.
- E10: Water pressure too low.
- E12: Fan fault.
- E44: Flame signal fault.
Note: the code format (A.. / E..) differs by series on newer Wolf models — contact our technicians for an accurate diagnosis.