Worcester Bosch Pump Armature Danfoss 87161427780

The Worcester Bosch 87161427780 is the armature for the Danfoss circulating pump used on a number of Worcester Bosch oil-fired appliances. It is the rotating part of the pump motor: the stator coil creates a magnetic field, the armature turns inside it, and that rotation drives the impeller that pushes water around the heating and hot water circuit. A failed armature leaves the pump unable to circulate, so the boiler fires but heat does not reach the system.

• The pump motor hums or buzzes but the impeller does not turn and no water is circulated.
• Radiators or the stored hot water stay cold while the burner is running normally.
• Grinding, rumbling or scraping noise coming from the pump body.
• The pump casing becomes unusually hot during operation.
• The appliance repeatedly trips on overheat or lockout because flow through the boiler has stopped.

• Confirm the appliance model against the compatibility list before ordering, as this armature suits specific Danesmoor FS and Greenstar Heatslave variants.
• Check that the pump fitted to the appliance is the Danfoss type this armature is intended for.
• While the pump is stripped down, inspect the seals and O-rings and replace any that are hardened, split or swollen.
• Oil-fired appliance work should be carried out by a competent engineer, with the appliance isolated and safely re-commissioned afterwards.