OEM Carrier Draft Inducer Pressure Switch 0.18" WC for Model PY4GNAB30040NA

This is the factory OEM replacement draft pressure proving switch for the Carrier PY4GNAB30040NA packaged unit. The pressure switch monitors negative pressure created by the inducer motor to verify safe venting conditions before allowing the ignition sequence to proceed. When this switch fails or sticks open, the control board cannot confirm that the flue is drafting correctly — resulting in a no-heat lockout condition that typically occurs before any ignition attempt. A failed pressure switch is one of the most common causes of furnace lockout fault codes.

• Specs: 0.18" Water Column (WC) set point | SPST (Single Pole, Single Throw) | Draft inducer proving type | Compatible with 24V control circuits | Cross-references Honeywell IS20224-5236 and 1938D2/B
• OEM vs Generic: OEM switches are calibrated to exact factory WC tolerances. Off-spec aftermarket switches can trip too early or too late, causing nuisance lockouts or — more dangerously — allowing ignition under unsafe venting conditions. Always match the WC rating precisely.
• Install difficulty: 2/5 — Power down and lockout the unit before servicing. Tools needed: 1/4" nut driver, flat-head screwdriver, and a multimeter to confirm switch continuity. Note the hose port orientation before removing the old switch. Replacement typically takes under 20 minutes.
• Warranty & Shipping: 1-year OEM manufacturer warranty. In-stock orders ship same business day from our warehouse. Note: OEM part number HK06WC061 is superseded — this listing ships the current authorized replacement, HK06MB061, which is a direct, drop-in substitution.

Compatibility: Verified fit for Carrier model PY4GNAB30040NA packaged unit. This switch also fits select Bryant and Payne models sharing the same inducer assembly. Always confirm the 0.18" WC rating on your unit's wiring diagram or existing switch label before ordering. Our team is available to verify fitment — contact us before you order if you have any questions.