hp-Technik 18/24 coupling

The hp-Technik 18/24 coupling, listed under oil filters, coils, tubes & hoses, is a connector used in oil supply lines within burner systems. Its catalogue and manufacturer codes are 543.505.006 and 0820671, 84139100, 543.505.006. This coupling joins two sections of pipe, hose, or fitting, typically between the oil pump, filter, or preheater, ensuring a sealed connection that withstands the pressure and temperature of fuel oil. Couplings of this type are selected by their thread size and type (often BSP), nominal bore diameter, and material compatibility with the fuel (commonly brass or steel). When replacing such a coupling, verify the thread pitch and seal method—either a bonded washer, copper washer, or thread sealant rated for oil. Incorrect fit can cause leaks, leading to air ingress into the pump and poor atomisation, or oil drips that create a fire hazard. The coupling itself has no moving parts, but its seal surface must be clean and undamaged. In the fuel train, a coupling is typically installed between the pump outlet and the flexible hose or between the hose and the preheater. A loose or cracked coupling can mimic pump failure symptoms: low burner pressure, erratic ignition, or sooting. Always replace sealing washers when refitting a coupling, and torque to the manufacturer’s specification—overtightening can distort the seat.