Honeywell Control box TFI812 mod.5 02601

This is a Honeywell burner control box, model TFI812 mod.5, catalogue number 02601. It is a flame safeguard relay for gas burners, managing the ignition and safety sequence. The safety time is 5 seconds, pre-ignition time is 15 seconds. It supports flame detection via an ionisation probe or an infra-red flicker detector. It is intended for two-stage gas burners.

Control boxes of this type must be selected by matching the exact series and type designation, safety time, supply voltage, flame detection method, and base/plug pattern. These parameters are not interchangeable between series, even within the same brand. The replacement must be compatible with the existing gas valve, ignition transformer, fan, and pressure switches. Verify the model and series against the original before ordering.

When the control box does not receive a flame signal within the safety time, it locks out and the burner shuts down. This can happen when the flame detector fails or the flame signal path is interrupted. A lockout usually requires a manual reset after the cause is corrected. Verify the flame detector, wiring, and the safety time setting.