hp-Technik Piston 0840758

The hp-Technik Piston 0840758 is a precision component made of hardened steel, designed for use in the bypass valve of hp-Technik B-GHG/FDR 25 liquid fuel pumps. It functions as a pressure regulation element, ensuring accurate maintenance of system pressure. This piston is a replacement part for the specified pump series and is manufactured in Germany.

Parts of this type are selected by matching the pump model and series, as well as the piston's diameter, length, and sealing geometry to the original specification. Before ordering, confirm the pump series and revision, as internal components may vary between production batches. Inspect the pump bore for damage and replace associated seals and gaskets during installation.

Common failure modes include surface wear, scoring from contaminated oil, or sticking due to varnish buildup. These can cause unstable pressure, poor atomisation, or incomplete cut-off in the burner system. If the bypass valve loses sealing or does not hold pressure, replacing the piston typically resolves the issue.