OEM Carrier Draft Inducer Pressure Switch 0.18" W.C. for Model PY4GPAB42090AA

This is the OEM factory-specified draft pressure switch for the Carrier PY4GPAB42090AA packaged unit. The pressure switch monitors negative pressure created by the inducer motor to confirm safe venting before allowing ignition to proceed. When this switch fails or sticks open, the control board cannot verify that combustion gases are being properly exhausted — resulting in a hard lockout with no heating output. Common symptoms include the inducer motor running continuously with no ignition attempt, an error code indicating a pressure switch fault, or intermittent no-heat calls that reset only after power cycling the unit.

• Specs: 0.18" W.C. (inches water column) set point | Single-port, normally open | Replaces Honeywell IS20224-5236 | OEM Part Number HK06WC061 (superseded by HK06MB061)
• OEM vs Generic: This OEM-equivalent pressure switch is manufactured to exact factory trip-point tolerance. Generic switches can have ±10–15% W.C. variance, causing nuisance lockouts or — more dangerously — failing to detect a blocked flue condition.
• Install Difficulty: 2/5 — Power off the unit at the disconnect before beginning. Tools needed: 1/4" and 5/16" nut driver, needle-nose pliers, and a short length of replacement tubing if the original hose is cracked. Photograph all hose and wire connections before removal. Confirm the inducer wheel and hose barb are clear of debris before installing the new switch.
• Warranty: 1-year replacement warranty. In-stock and ships same business day from our warehouse.

Compatibility: Designed for the Carrier PY4GPAB42090AA packaged unit. Also fits select Bryant and Payne models requiring a 0.18" W.C. draft proving switch — always verify the W.C. rating on your existing switch or unit wiring diagram before ordering. Our HVAC parts specialists are available to confirm fitment prior to purchase.