OEM Carrier Draft Pressure Switch 0.18" WC for Model PY4GNAA36090AA

This OEM Carrier draft pressure proving switch (part# HK06WC061, superseded by HK06MB061) is the factory-specified replacement for the Carrier PY4GNAA36090AA packaged unit. The pressure switch monitors negative pressure created by the inducer motor to verify safe flue venting before allowing ignition. When the switch fails — either stuck open or stuck closed — the control board cannot confirm inducer operation, causing the system to lock out before the burners ever fire. Common symptoms include a furnace that starts the inducer but never reaches ignition, a blinking fault code indicating a pressure switch fault, or a unit that attempts a heat call but shuts down within seconds.

• Specs: 0.18" Water Column (W.C.) setpoint | SPST normally open | Replaces OEM part# HK06WC061 | Current OEM part# HK06MB061 | Also cross-references Honeywell IS20224-5236
• OEM vs Generic: This is a genuine OEM Carrier part manufactured to exact factory tolerances. Generic pressure switches frequently carry wider W.C. tolerance bands, which can cause nuisance lockouts or, worse, allow ignition under unsafe draft conditions.
• Install difficulty: 2/5 — Disconnect power before servicing. Tools needed: 1/4" nut driver, flathead screwdriver, multimeter (to verify switch continuity). Photograph hose routing before removal. Replace tubing if cracked — a leaking hose mimics a failed switch.
• Warranty: 1-year OEM factory warranty. In-stock and ships same business day from our warehouse.

Compatibility: Designed for the Carrier PY4GNAA36090AA packaged unit. Also fits select Bryant and Payne models with the same 0.18" W.C. pressure switch specification — verify your unit's data plate and existing part number before ordering. Have a question about fitment? Our HVAC parts specialists confirm compatibility before you buy.