OEM Carrier Draft Pressure Switch 0.18" WC for Model PY4GPAB36090AA

This OEM draft inducer pressure switch is the factory-specified replacement for the Carrier PY4GPAB36090AA packaged unit. The pressure switch monitors the negative pressure created by the inducer motor to verify proper venting before allowing the ignition sequence to proceed. When it fails or drifts out of calibration, the control board cannot confirm safe combustion airflow and will lock out the unit — typically with a fault code before the burners ever fire. Common symptoms include a furnace that won't ignite, an inducer that runs but heating never starts, or a system stuck in a pre-ignition lockout loop.

• Specs: 0.18" Water Column (W.C.) set point | SPST normally open | Draft-proving (closes on negative pressure) | OEM part number HK06WC061, superseded to HK06MB061 | Honeywell-manufactured for Carrier/Bryant/Payne
• OEM vs Generic: This is a factory-matched OEM switch calibrated to the exact 0.18" W.C. trip point required by the PY4GPAB36090AA control board. Off-spec aftermarket switches with loose tolerances can cause nuisance lockouts or — more dangerously — allow ignition under inadequate draft conditions.
• Install difficulty: 2/5 — Shut off power and gas before servicing. Locate the switch on or near the inducer housing. Disconnect the single rubber pressure hose and two wire terminals. Swap the switch, reconnect hose and terminals, restore power. Tools needed: flat-head screwdriver, needle-nose pliers, manometer (to verify draft after install). Always clear any fault codes after replacement.
• Warranty: 1-year OEM manufacturer warranty. In stock and ships same business day from our warehouse.

Compatibility: Direct OEM replacement for Carrier model PY4GPAB36090AA. OEM part number HK06WC061, current superseding part number HK06MB061. Also fits select Bryant and Payne models with the same 0.18" W.C. pressure switch specification — verify your unit's data plate and existing part number before ordering. Have questions about fitment? Our HVAC parts team confirms compatibility before you buy.