Danfoss Oil pump BFP21L5 071N7172

The Danfoss BFP21L5 oil pump (SKU 071N7172) is a gear pump designed for residential and commercial burners using light fuel types. It operates within a pressure range of 7000–20000 mbar and supports fuel consumption up to 42 l/h. The pump features a shut-off function, a diaphragm regulator, and fuel outlets on both left and right sides. It is compatible with single-pipe or two-pipe systems, with excess fuel returned to the tank in two-pipe mode and a bypass in single-pipe mode. The pump has an IP40 protection class and operates in ambient temperatures from -20 to 70 °C.

When selecting a replacement oil pump of this type, ensure the shaft type and standard (e.g., EN225) match the burner's coupling. Verify the pressure range and fuel consumption capacity align with the system's requirements. Check the inlet pressure maximum (2000 mbar) and the maximum pressure in the suction/return line (2 bar) to avoid overpressure. Confirm the pump's configuration for single-pipe or two-pipe operation, as the screw is absent in single-tube mode. Also, match the viscosity range of the fuel (1.8-12.0 cst) and the filter specifications (11/200 cm2/microns) to the existing setup.

Common failures in oil pumps of this kind include loss of pressure due to worn gears or a faulty diaphragm regulator, leading to incomplete combustion or burner shutdown. A clogged filter can cause fuel starvation, resulting in erratic flame or no ignition. Leaks may occur at seals or connections, visible as fuel drips. If the shut-off valve fails, fuel may continue to flow after the burner stops, causing flooding. Check the fuel pressure and inspect the filter and seals for wear or blockage.