Nor East Controls 30067756 322 Hex Nut The York S1 024 19082 020 Sequencer Relay The York S1 024 19082 020 Sequencer Relay is a high performance 24V heat sequencer engineered to manage the staged activation and deactivation of electric heating elements within a furnace or air handler providing flexibility for various HVACR equipment configurations Keeping these replacement valve nuts in your service kit is standard practice for contractors managing industrial automation components and commercial fluid control systems this hex nut ensures secure mechanical stability under heavy vibration and thermal cycling common in HVACR valve maintenance