As a veteran-grade HVAC sequencer replacement

Does this replace specific Jard or MARS2 numbers

and FS7-4W series

If you are troubleshooting a furnace short cycling issue or a lockout condition where the burner ignition fails after a few seconds

Broad Compatibility: Serves as a direct HVAC sequencer replacement for most major OEM furnace and heat pump brands

Robertshaw 5500-136 Infinite Switch As a veteran-grade HVAC sequencerThe Robertshaw 5500 136 Infinite Switch is a vintage spec, 120V electrical control designed for precise proportional power regulation in resistive heating applications. Engineered as a voltage sensing parallel circuit control, this 120V infinite switch is a direct replacement for INF 120 and VSI series components used in commercial and residential foodservice equipment. It features a push to turn (PTT) safety mechanism and a compact housing that