Danfoss Oil pump BFP21 L3 071N7170

The Danfoss BFP21 L3 oil pump (SKU 071N7170) is a gear pump designed for small and medium-sized household burners with fuel consumption up to 42 l/h. It operates within a pressure range of 7000–20000 mbar and handles fuel viscosity from 1.8 to 12.0 cst (mm2/s). The pump features a built-in filter with an area of 11 cm2 and a cross-section of 200 microns, and it supports both single-pipe and two-pipe systems. It is suitable for ambient temperatures from -20 to 70 °C and fuel temperatures from 0 to 70 °C, with a protection class of IP40. The shaft is made of EN225 material and rotates at speeds between 2400 and 3450 min.

When selecting a replacement oil pump of this type, ensure the shaft standard (e.g., EN225) and rotation speed range match the burner's drive. Verify the pressure range and factory settings (typically 10 ±1 bar) align with the system 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 fuel consumption capacity (up to 42 l/h) is sufficient for the burner's nozzle output. Also, match the system type (single-pipe or two-pipe) and ensure the mounting dimensions and shaft torque (0.1 Nm) are compatible.

Common failures in gear pumps of this kind include loss of pressure due to worn gears or a clogged filter, leading to burner ignition issues or unstable flame. If the pump fails to deliver fuel, check the built-in filter for debris and verify the shaft rotates freely. Overheating or excessive noise may indicate bearing wear or misalignment. In two-pipe systems, a faulty bypass can cause fuel to leak or pressure fluctuations. Always inspect for fuel leaks around seals and connections, as these can lead to air ingress and poor combustion.