The IBC Technologies P-9143 Return Water Pipe is a genuine replacement component designed for IBC SL 80-399 and SL 80-399 (2.5) high-efficiency condensing boilers. It carries cooler return water from the hydronic heating system back to the boiler’s heat exchanger for reheating and recirculation. This component supports proper water flow and reliable heating system operation. Ideal for... https://www.partshnc.com/p-9143-ibc-technologies-return-water-pipe-sl-399