OEM Carrier Draft Pressure Switch 0.18" WC for Model PY4GNAC30040NA (HK06WC061 / HK06MB061)

This OEM Carrier draft pressure proving switch is the factory-specified replacement for the Carrier PY4GNAC30040NA packaged unit. The pressure switch monitors the negative pressure (draft) created by the inducer motor before allowing the ignition sequence to begin. When it fails or sticks open, the control board cannot confirm that combustion gases are being safely exhausted — resulting in a no-heat lockout condition, typically before the igniter ever fires.

• Specs: 0.18" W.C. (water column) rating | Normally open, closes on draft | Replaces OEM part HK06WC061 (superseded by HK06MB061) | Also replaces Honeywell IS20224-5236 | Compatible with Carrier, Bryant, and Payne furnaces, packaged units, heat pumps, and air handlers
• OEM vs Generic: This is a genuine OEM-equivalent part built to factory W.C. specifications. Generic pressure switches often carry ±10–15% set-point variance, which can cause nuisance lockouts or — worse — fail to detect a true venting fault. Exact W.C. rating is critical for safe furnace operation.
• Install difficulty: 2/5 — Shut off power and gas before servicing. Tools needed: 1/4" nut driver, flathead screwdriver, and a manometer (recommended to verify draft after replacement). Disconnect the rubber hose and two wire leads, swap the switch, and reconnect. Always inspect the hose for cracks or blockages while the switch is removed.
• Warranty: 1-year OEM warranty. In stock and ships same business day from our warehouse.

Compatibility: Fits Carrier model PY4GNAC30040NA and related Bryant and Payne packaged units using the 0.18" W.C. draft pressure switch specification. Verify W.C. rating on your unit's wiring diagram or data plate before ordering. Not sure it fits? Our HVAC parts specialists verify fitment before you buy — call or chat today.