EBM PAPST Centrifugal fan RLH120/0038-3038LH 55460.96520

This is an EBM Papst fan, model RLH120/0038-3038LH, type designation 41938, designed for Thermona gas boilers. It supplies combustion air to the burner and, in room-sealed appliances, expels flue gases. The catalogue states that this fan can be configured with mains, PWM, or 0–10 V control modes, and with axial, radial, or tangential outlet orientation. Its design features include durable components.

Parts of this type supply combustion air to the burner and, in sealed appliances, expel flue gases. When replacing one, match the air flow and pressure rating, the outlet orientation (axial, radial, or tangential), the impeller diameter, and the voltage/control mode (mains, PWM, or 0–10 V). The flange pattern must match the burner mounting. Choose a replacement with the same control interface, as a different signal type may not be accepted by the burner control.

Typical failures include worn bearings, imbalance from deposits on the impeller, a failed run capacitor, or speed feedback errors that the boiler interprets as an airflow fault. Because the speed signal is often used for safety checks, a faulty fan can cause lockout even if the motor runs. Check for unusual noise or vibration, inspect the impeller for deposits, and verify that the speed feedback signal is intact.