OEM Carrier Draft Pressure Switch 0.18" WC for Model PY4GPAB42090NA (HK06WC061 / HK06MB061)

This OEM Carrier draft proving pressure switch is the factory-specified replacement for the Carrier PY4GPAB42090NA packaged unit. The pressure switch monitors negative pressure created by the inducer motor to confirm proper venting before allowing ignition. When it fails or sticks open, the control board cannot verify inducer operation and will lock out the system — resulting in a no-heat call with no spark, no gas, and often a fault code pointing to the pressure circuit.

• Specs: 0.18" Water Column (W.C.) | SPST normally open | Factory OEM rating | Cross-references: HK06WC061, HK06MB061, Honeywell IS20224-5236, 1938D2/B
• OEM vs Generic: OEM switches are calibrated to exact W.C. setpoints at the factory. An off-spec generic switch can trigger nuisance lockouts or — worse — allow ignition under unsafe vent conditions. Always match the W.C. rating exactly to the original.
• Install difficulty: 2/5 — Shut off power and gas before servicing. Tools needed: 1/4" nut driver, flathead screwdriver, hose clamp pliers. Photograph or label the pressure tubing port before disconnecting. Verify inducer motor operation before condemning the switch — blocked flue or cracked tubing causes identical symptoms.
• Warranty: 1-year OEM manufacturer warranty. In-stock orders ship same business day from our warehouse.

Compatibility: Confirmed fit for Carrier model PY4GPAB42090NA packaged units. OEM part number HK06WC061 has been superseded by HK06MB061 — both numbers are fulfilled by the same current OEM part. Also fits select Bryant and Payne models using the same 0.18" W.C. switch specification. Verify your unit's data plate W.C. rating before ordering. Our fitment team is available to confirm compatibility before you buy.