OEM Carrier Draft Pressure Switch 0.18" WC for Model PY4GNAB48115NA

This OEM draft proving pressure switch is the factory-specified replacement for the Carrier PY4GNAB48115NA packaged unit. The pressure switch monitors negative pressure created by the inducer motor to confirm safe draft conditions before allowing the ignition sequence to proceed. When this switch fails — or if the inducer, flue, or hose is compromised — the control board receives no proof-of-draft signal and the unit will lock out, delivering no heat. Common symptoms include the furnace failing to advance past the inducer stage, a blinking fault code for "pressure switch open," or the system starting then immediately shutting down.

• Specs: 0.18" Water Column (W.C.) set point | SPST normally open | OEM Part# HK06WC061 (superseded by HK06MB061) | Honeywell IS20224-5236 cross-reference
• OEM vs Generic: OEM switches are factory-calibrated to exact W.C. tolerances. Generic switches often drift ±0.03" W.C. or more, causing nuisance lockouts or — worse — failing to detect a true blocked flue condition, which is a safety hazard.
• Install difficulty: 2/5 — Power off the unit at the disconnect before starting. Tools needed: 1/4" and 5/16" nut drivers, needle-nose pliers, and a short length of replacement 3/16" I.D. silicone hose. Always inspect the rubber pressure hose for cracks or blockages before condemning the switch itself.
• Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Designed for the Carrier PY4GNAB48115NA packaged unit. Note that OEM part HK06WC061 has been superseded by HK06MB061 — both are functionally identical direct replacements. Verify the 0.18" W.C. rating on your unit's wiring diagram or existing switch label before ordering. Our fitment team is available to confirm compatibility before you buy — ships same day when ordered before 3 PM.