Installed Grundfos Alpha HWR. Drained down water heater in order to remove existing recirculation line tied into the bottom. Removed old pump and replaced it with a new Grundfos. Tied recirculation line in cold inlet in a manner that would better serve the parallel design of water heaters. Added check valves in correct locations on recirculation line and cold inlet. Tested thoroughly and ensured customer was receiving proper hot water recirculation.