The Rheem-Ruud PD425144 Pressure Switch Kit -0.30" PF is a genuine OEM safety component designed for compatible Rheem and Ruud gas furnaces. It monitors negative air pressure created by the furnace’s combustion and venting system, allowing the unit to operate only when proper draft conditions are detected. If pressure falls outside the required range, the switch opens the control circ... https://www.partshnc.com/pd425144-rheem-ruud-pressure-switch-030pf