De Dietrich 7665194 NRG118 - D19.6 -25kW fan

This fan, listed under De Dietrich with manufacturer codes 7665194, NRG118/0800-3612-030231, and catalogue article 375.145.057, belongs to the category of fans and flue gas exhausters. Fans of this type supply combustion air and, in room-sealed appliances, drive flue gases out of the system. In modulating premix burners, the fan speed determines the firing rate; the burner control varies the speed and the gas valve follows the air flow. When replacing a fan, selection is based on required air flow and pressure, the direction and orientation of the outlet, impeller diameter, operating voltage, and control mode (mains, PWM, 0–10 V). The flange pattern must also match the mounting on the burner or boiler. Typical failures include worn bearings, imbalance caused by deposits on the impeller, a failed capacitor, or speed feedback errors that the burner control interprets as an airflow fault. The fan works with the air pressure switch, which must confirm airflow during the pre-purge and running phases, and with the burner control that modulates the speed. In premix systems, correct fan operation is essential for stable combustion and safe start-up. No further specifics about this particular article, such as voltage, dimensions, or compatible appliance models, are available from the supplied data.