Vaillant 0020221618 Cable, pump Grundfos

The Vaillant pump cable, part number 0020221618, is a wiring lead that connects the circulation pump to the appliance's electrical supply. It sits within the Cables, Leads & Wiring Harnesses group of Vaillant spares and is listed against Grundfos pump applications.

The cable carries the supply that drives the pump motor, so the pump can circulate water around the heating circuit as the appliance's control sequence demands. A cable with a broken conductor, a loose terminal or damaged insulation can interrupt that supply and stop the pump from running, even when the pump itself is sound. Replacing the lead restores a clean electrical path between the control side of the appliance and the pump.

Because the pump is a moving component working in a warm, wet environment, the lead and its connectors are exposed to vibration and heat cycling over the life of the appliance. Inspecting the cable alongside the pump during a service or repair is good practice.

• The pump does not run when the appliance calls for heat
• The pump starts and stops intermittently during a heating cycle
• Overheat or lockout faults traced back to a pump that is not circulating
• Visible damage to the cable, plug, terminal or insulation
• No continuity on the pump supply when the lead is tested

• This part is fitted to a gas appliance; installation must be carried out by a Gas Safe registered engineer.
• Check the model and serial number on the appliance data badge to confirm the cable is correct for your unit.
• Match the part number 0020221618 against the marking on the original cable before ordering.
• Inspect the pump and its connections at the same time, as a faulty pump can produce the same symptoms as a faulty lead.