HVAC, Heat Pump & Boiler Fault Codes Directory
Troubleshoot error codes for Daikin, Mitsubishi, Vaillant, Worcester Bosch, Viessmann, Carrier, and NIBE:
❄️ Daikin U4 — Transmission Error Between Indoor and Outdoor Unit❄️ Vaillant F28 — Failure During Ignition / No Gas Supply❄️ Mitsubishi Electric P8 — Pipe Temperature Abnormality❄️ Worcester Bosch EA — Flame Not Detected❄️ Viessmann F4 — Burner Lockout (No Flame Signal)❄️ Carrier Code 33 — Limit Switch / Flame Rollout Open❄️ NIBE Alarm 51 — Low Brine Flow / Low Pressure