Understanding Boiler Error Codes

Modern boilers display error codes to help diagnose faults. Rather than being alarming, most codes point to a specific, fixable issue. Here are the most common codes for the UK's most popular brands.

Worcester Bosch error codes

• EA 229: Ignition fault — usually a faulty ignition lead or dirty electrodes. Gas Safe engineer required.
• F.28 / F.29: Ignition failure — low gas pressure or a faulty gas valve.
• F.75: Pressure sensor fault — requires engineer inspection.
• CL: Comfort Level setting — not an error, just a parameter display.

Vaillant error codes

• F.22: Low water pressure — re-pressurise the system first. If persistent, call an engineer.
• F.28: Ignition failure — may be a gas supply issue or faulty igniter.
• F.75: Pressure sensor or pump fault.

Baxi error codes

• E168: Low gas pressure — check other appliances work. If so, call an engineer.
• E160: Overheat fault — check the system isn't air-locked and pressure is correct.
• E110: Overheat safety device operated — engineer required.

Ideal error codes

• F1: Low pressure — re-pressurise first.
• F2: Flame loss — gas supply check, then call engineer if persistent.
• L1: Overheat — check pressure and bleed radiators. Engineer if persistent.

What to do next

For any persistent fault code after a reset and basic checks, call a Gas Safe engineer. We carry most common replacement parts in our vans for same-day repairs. Book a repair with Corby Boiler Installations.