OEM Carrier Draft Pressure Switch 0.18" WC for Model PY4GNAB30040AA

This OEM draft proving pressure switch (part #HK06WC061, superseded by HK06MB061) is the factory-specified replacement for the Carrier PY4GNAB30040AA packaged unit. The pressure switch monitors the negative pressure created by the inducer (draft) motor to confirm that proper venting is established before allowing the ignition sequence to proceed. When it fails — or when the tubing collapses, clogs, or the inducer motor weakens — the switch stays open, putting the system into a no-heat lockout condition before a single spark fires.

• Specs: 0.18" Water Column (WC) setpoint | Normally Open (N.O.) | Single-port | Honeywell-manufactured (OEM IS20224-5236) | Factory-authorized Carrier replacement part
• OEM vs Generic: OEM pressure switches are calibrated to exact WC setpoints at the factory. Off-brand substitutes often carry ±0.05" WC tolerance drift, leading to nuisance lockouts or — worse — allowing ignition without confirmed draft, creating a safety risk.
• Install difficulty: 2/5 — Power down the unit at the disconnect before servicing. Tools needed: flathead screwdriver, needle-nose pliers, manometer (recommended to verify inducer pressure). Inspect the rubber sensing hose for cracks or blockages before condemning the switch alone.
• Warranty: 1-year OEM factory warranty. Ships same business day from our warehouse when ordered before cut-off.

Compatibility: Fits Carrier PY4GNAB30040AA packaged units. Also compatible with select Bryant and Payne models sharing the 0.18" WC draft pressure specification. Note: HK06WC061 has been superseded by factory part HK06MB061 — both part numbers are fulfilled with the current OEM revision. Verify the WC rating on the original switch label before ordering. Questions? Our HVAC parts specialists verify fitment before you buy — in stock and ready to ship today.