The Geo-Flo Pump Sharing Relay Control allows two separate systems(such as geothermal heat pumps or hydronic air handlers) to control a single pumping system such as a flow center or a chilled water pump. Whenever either of the two sets of 24VAC terminals receives a 24VAC signal the controller (relay RY1 or RY2) switches 115/208/230 VAC power from the source to the pump(s). The board is clearly labeled with 24 VAC, 240V IN, and 240 V OUT for ease of installation. The control also features two LEDs which illuminates when a 24 VAC signal is received. An additional pump sharing relay can be added to allow three units to energize a pump. For more information, see the IOM link at upper left. It is not recommended to use this controller to energize permanent magnet ECM pumps such as the Grundfos Magna3 via high power (208/230 V) due to the high in-rush current from the pumps. These ECM pumps should be controlled via low voltage/contact closure as is done with our 3808 Pump Enable Control.