a reading of "OL" or open loop indicates a broken coil

Enhanced Durability: Constructed with robust materials to handle the radial loads and high temperatures of continuous HVAC operation

Ready for Install: Packaged with essential hardware including mounting screws and harness connectors for streamlined service

40VA Load Capacity: Optimized for commercial control circuits

making it a staple for contractors managing residential and light commercial HVAC systems

Lochinvar & A.O. Smith 100278231 Coupler 30067439-890 a reading of "OL" orThe Lochinvar & A. O. Smith 100278231 Coupler is a precision engineered pump coupler replacement designed for high performance hydronic and domestic hot water systems. As a critical mechanical link between the motor and the pump assembly, this genuine OEM part ensures smooth torque transmission while compensating for minor shaft misalignments that can lead to premature bearing failure. This specific model is the direct technical replacement for the