Vaillant Circulation Pump VP5 Grundfos VAILLANT160928

The Vaillant 160928 is a VP5/Grundfos pattern circulation pump used in Vaillant TURBOmax and THERMOcompact boilers. It is the primary pump that moves water around the heating circuit, drawing heated water from the boiler heat exchanger and pushing it through the radiators and pipework before it returns to be reheated. The pump sits in the boiler casing and is driven by the appliance's control board, so a failure here stops circulation across the whole system.

• Radiators stay cold or heat unevenly while the boiler is firing and the burner is lit
• The pump body runs hot, hums loudly, or makes a grinding or rumbling noise when running
• The boiler locks out on an overheat or flow/return temperature fault shortly after ignition
• Little or no temperature difference between the flow and return pipes at the boiler
• Water weeping from the pump body, flange or gland area

• Read the boiler data badge and confirm the fitted pump carries the number 160928
• Identify the exact boiler model and version, as TURBOmax and THERMOcompact ranges use different pump variants across production runs
• Check the condition of the pump gaskets and seals, and order replacements if the existing ones are disturbed during removal
• Isolate the electrical supply and drain or isolate the water circuit before removing the pump