OEM Carrier Draft Inducer Pressure Switch 0.18" WC for Model PY4GNAB36090NA

This OEM Carrier draft inducer pressure switch is the factory-specified replacement for the Carrier PY4GNAB36090NA packaged unit. Rated at 0.18" water column (WC), it monitors negative pressure created by the inducer motor to confirm proper venting before the ignition sequence begins. When this switch fails or sticks open, the control board cannot verify safe draft conditions — resulting in a no-heat lockout, repeated ignition attempts with no flame, or a furnace/packaged unit that runs the inducer continuously without advancing to the heating cycle.

• Specs: 0.18" WC set point | SPST (Single Pole, Single Throw) | Normally Open | OEM Part# HK06WC061 (superseded by HK06MB061) | Cross-reference: Honeywell IS20224-5236
• OEM vs Generic: This is a genuine Carrier OEM pressure switch, factory-calibrated to the exact 0.18" WC trip point. Generic switches often carry ±10–15% tolerance on set point, risking nuisance lockouts or — more dangerously — allowing the furnace to fire without confirmed draft.
• Install difficulty: 2/5 — Shut off power and gas before servicing. Tools needed: 1/4" nut driver, flat-head screwdriver, manometer (recommended to verify draft). Disconnect the rubber hose and two quick-connect terminals, swap switch, reconnect, and restore power. Always test draft pressure and cycle the unit through a full heating sequence to confirm normal operation.
• Warranty: 1-year OEM factory warranty against defects. Ships same business day from our warehouse when ordered by cutoff time.

Compatibility: Designed for Carrier model PY4GNAB36090NA packaged gas/electric units. Note that OEM part HK06WC061 has been superseded by HK06MB061 — both are fully interchangeable and covered by this listing. Verify the 0.18" WC rating on your unit's wiring diagram or existing switch body before ordering. Have a question about fitment? Our HVAC parts specialists confirm compatibility before you buy — in stock and ships today.