There is a lot of talk these days about heat pump water heaters being the most environmentally friendly and efficient water heaters available. However, owners have reported issues when using heat pump water heaters in conjunction with a dedicated recirculation loop. The issue being that the heat pump water heater requires a certain temperature differential between the water coming into the water heater and the water temperature in the water heater. With a continuously running recirculation pump the differential is never met so a heating cycle is not initiated and the water in the heater cools down leaving the home owner with mildly warm water. You can read about this in the Rheem technical bulletin. Rheem recommends only using the unit in High Demand mode or Electric only mode and says that Energy Saver mode won't work well.
Fortunately the Smart Recirculation Control 32 solves this problem for heat pump water heater owners as our control turns the pump off when the loop is up to temperature preventing the heat pump water heater from cooling off thus restoring peak efficiency of your water heater investment while still providing you with the convenience of hot water at your fixtures.