OEM Carrier Draft Pressure Switch 0.18" WC for Model PY4GEAB42090AA

This OEM draft pressure proving switch is the factory-specified replacement for the Carrier PY4GEAB42090AA packaged unit. The pressure switch monitors negative pressure created by the inducer motor to confirm proper venting before allowing ignition to proceed. When it fails or gets stuck open, the control board never receives the "all-clear" signal — leaving you with a system that locks out before a single ignition attempt, often displaying a fault code related to the pressure switch or inducer circuit.

• Specs: 0.18" W.C. (water column) trip point | Single-port draft pressure switch | 24V control circuit compatible | Replaces OEM part numbers HK06WC061 and superseding part HK06MB061 | Also cross-references Honeywell IS20224-5236
• OEM vs Generic: This is a genuine OEM-spec switch calibrated to the exact 0.18" W.C. set point required by the PY4GEAB42090AA. Aftermarket switches with looser tolerances can cause nuisance lockouts or, worse, allow ignition under unsafe draft conditions.
• Install difficulty: 2/5 — Power down the unit at the disconnect before beginning. Tools needed: 1/4" nut driver, needle-nose pliers, and a short length of 3/16" I.D. tubing if the existing hose shows cracks. Inspect the inducer port and tubing for blockages before installing — a clogged hose is the #1 cause of premature switch failure.
• Warranty: 1-year OEM factory warranty against defects. Orders placed before our daily cutoff ship the same business day from our stocked warehouse.

Compatibility: Engineered for the Carrier PY4GEAB42090AA packaged unit. Also fits a broad range of Carrier, Bryant, and Payne furnaces, packaged units, heat pumps, and air handlers that specify the 0.18" W.C. pressure switch. Always verify the W.C. rating and hose port diameter on your unit's data plate before ordering. Our HVAC parts specialists are available to confirm fitment — reach out before you order if you have any questions.