De Dietrich S100036 RG148 1200-3633-010202 fan

This fan is a combustion air supply component and, in room‑sealed appliances, also drives the flue gases out. The speed of such a fan determines the firing rate in modulating premix burners: the burner control varies the fan speed and the gas valve follows. Parts of this type are selected by required air flow and pressure, the direction and orientation of the outlet, impeller diameter, voltage, control mode (mains, PWM, 0‑10 V), and the flange pattern that matches the mixer or burner head. When replacing a fan of this class, check the mounting dimensions and the electrical connection. Typical failure modes include worn bearings, imbalance caused by deposits on the impeller, a failed run capacitor, and speed feedback errors that the boiler reports as an airflow fault. The fan works closely with the air pressure switch that confirms adequate airflow before ignition; if the fan is replaced, ensure the pressure switch setting and sensing line are also inspected.