OEM Carrier Draft Pressure Switch 0.18" WC for Model PY4GNAA60090AA (HK06WC061 / HK06MB061)

This OEM Carrier draft pressure proving switch is the factory-specified replacement for the Carrier PY4GNAA60090AA packaged unit. The pressure switch monitors negative pressure generated by the inducer motor to confirm proper venting before allowing the ignition sequence to proceed. When it fails or sticks open, the furnace or packaged unit will lock out before ignition — often displaying a fault code — leaving you with no heat. A failed pressure switch is one of the most common causes of a no-heat call that does not involve the gas valve or igniter.

• Specs: 0.18" Water Column (WC) | SPST normally open | Draft / inducer proving type | OEM part HK06WC061, superseded to HK06MB061 — both are fully interchangeable
• OEM vs Generic: OEM switches are calibrated to ±0.01" WC factory tolerance. Off-brand switches with loose tolerances can nuisance-trip or fail to open on a real venting fault — a serious safety risk. Always use OEM on gas-fired equipment.
• Install difficulty: 2/5 — Shut off power and gas before servicing. Tools needed: 1/4" nut driver, flathead screwdriver, manometer (for verification). Disconnect the rubber hose and two wires, swap the switch, reconnect, and verify inducer draft pressure. Always check the hose for cracks or blockages before condemning the switch.
• Warranty: 1-year OEM factory warranty against defects. Ships same business day from our warehouse when ordered before cutoff.

Compatibility: Fits Carrier model PY4GNAA60090AA packaged unit. OEM part number HK06WC061 has been superseded by HK06MB061 — our listing ships the current active OEM part. Verify your unit's data plate and existing switch rating before ordering. Our fitment team is available to confirm compatibility before you buy.