hp-Technik PON7-D-R-3-20 oil pump

This is an hp-Technik oil pump, listed under catalogue article 543.520.020 and manufacturer code PON7-D-R-3-20, from the oil pumps category. Parts of this type draw fuel from the tank and deliver it to the nozzle at the pressure that determines the firing rate. The integral solenoid valve provides the sharp fuel cut-off required by the burner control. Such pumps are selected by rotation direction, single or two-pipe operation, capacity and pressure range, shaft and mounting pattern, and connection threads. On burners that handle heavier oil, a preheater is fitted to reduce viscosity for proper atomisation; an integrated or upstream filter protects the pump and nozzle from debris. When replacing an oil pump of this class, the key parameters to match are the drive shaft dimensions and rotation (clockwise or counter-clockwise as viewed from the shaft end), the pressure range and factory-set nozzle pressure, and the port configuration for one- or two-pipe systems. The solenoid coil voltage must also be verified against the burner control output; a mismatch will prevent the pump from stopping fuel flow cleanly. Common failure modes on such pumps include worn gears that reduce delivered pressure, weakened pressure regulation causing unstable firing, leaking shaft seals, and solenoid coil failure that leaves the burner unable to cut off on shutdown. The replacement unit should be installed with new gaskets and the shaft coupling checked for wear.