Worcester Bosch Pump Head 8716119850

The Worcester Bosch 8716119850 is a replacement pump head for Worcester Bosch domestic heating appliances. The head carries the motor, shaft and impeller, and bolts onto the pump body that sits in the boiler's primary water circuit. Its job is to move heated water around the system, so when the head fails, circulation stops and the boiler can no longer distribute heat.

• The boiler fires and reaches temperature but radiators stay cold or heat unevenly.
• A grinding, whining or humming noise comes from the pump area when the boiler runs.
• The pump head runs hot while the pipework around it stays cool, indicating the impeller is not turning.
• Circulation or overheat fault codes appear, or the boiler locks out shortly after starting.
• Water weeps from the joint between the pump head and the pump body.

• Read the part number off the existing pump head and match it to 8716119850, as Worcester Bosch used several pump variants across its ranges.
• Check the boiler's model and GC number against the appliance data badge to confirm the correct assembly.
• If the pump body, O-ring or gasket is worn or scaled, replace those parts at the same time as the head.