The NTI Boiler 6500706000 Pump ES2 3VK 63-7C-C US VER Step 2 is a circulation pump designed for NTI boiler and hydronic HVAC systems. It operates by using a motor-driven impeller to circulate heated water efficiently through the boiler and connected heating circuits, supporting consistent heat transfer and temperature control. This pump is used with compatible NTI condensing boilers a... https://www.partshnc.com/nti-boiler-6500706000-pump-es2-3vk-63-7c-c-us-ver-step-2