EL2001 Mach 2.1 Designed to Handle 2 Pieces of Equipment Two 2-Speed Pumps or 1 Pump/Blower.

When using a third piece of equipment, needs the expander board: 53544 PCB: 1-Speed Expander Board VS510SZ

Please note: Circuit Boards are non-returnable items as they cannot be resold to another spa owner as new. On the bright side, you will also know that the board you receive is pristine, factory new and has never been installed before. See our return policy for further details. Circuit boards ARE COVERED under original Manufacturer's Limited Warranty.