OEM Carrier Draft Pressure Switch 0.18" WC for Model PY3GNAA30040NA

This OEM Carrier draft pressure switch is the factory-specified replacement for the Carrier PY3GNAA30040NA packaged gas unit. The pressure switch proves that the induced-draft blower has established adequate negative pressure before allowing the ignition sequence to proceed. When this switch fails or sticks open, the furnace control board detects an unsafe condition and halts operation — typically resulting in a no-heat lockout, an LED fault code for "pressure switch open," or repeated short-cycling before the burners ever light. Replacing this switch with the correct OEM part restores the factory safety interlock and gets heat back on quickly.

• Specs: 0.18" Water Column (W.C.) trip point | SPST normally open | Replaces OEM part numbers HK06WC061 and superseded part HK06MB061 | Also cross-references Honeywell IS20224-5236
• OEM vs Generic: OEM pressure switches are calibrated to exact W.C. tolerances at the factory. Off-brand substitutes often drift ±0.05" W.C. or more, causing nuisance lockouts or — worse — allowing ignition under unsafe draft conditions.
• Install difficulty: 2/5 — Shut off gas and power to the unit before starting. Tools needed: #2 Phillips screwdriver, 1/4" nut driver, needle-nose pliers. Photograph or label the hose port and wire spade connections before removal. Swap the rubber inducer hose and reconnect the two wire leads, then restore power and verify normal ignition sequence.
• Warranty: 1-year OEM factory warranty against defects. Ships same business day from our warehouse when ordered before cutoff.

Compatibility: Directly fits Carrier model PY3GNAA30040NA packaged gas units. This part also crosses to Bryant and Payne equipment sharing the same pressure switch specification. Always confirm the W.C. rating stamped on your existing switch matches 0.18" W.C. before ordering. Have questions about fitment? Our HVAC parts specialists verify compatibility before you buy — contact us today and we'll ship the right part fast.