OEM Carrier Furnace Pressure Switch 1.81" WC SPST — Model PG9MAA036080AFKA (HK06NB123)

This OEM pressure switch is the factory-specified replacement for the Carrier PG9MAA036080AFKA gas furnace. The pressure switch is a critical combustion-safety component — it monitors the negative pressure (draft) created by the inducer motor before allowing the ignition sequence to begin. When this switch fails, the furnace locks out before ignition, often throwing a pressure-switch fault code and leaving you with no heat. A failed switch typically results from a stuck-open or stuck-closed diaphragm, a cracked hose, or a failed inducer motor producing insufficient draft pressure.

• Specs: 1.81" W.C. (water column) set point | SPST (single-pole, single-throw) | Standard spade terminals | Standard vacuum hose ports | Factory-calibrated diaphragm for precise draft sensing
• OEM vs Generic: OEM pressure switches are factory-calibrated to exact W.C. tolerances for the PG9MAA036080AFKA. Generic switches may carry ±10–15% W.C. variance, risking nuisance lockouts or — more critically — allowing ignition under unsafe draft conditions.
• Install difficulty: 2/5 — Shut off gas and power before servicing. Tools needed: Phillips screwdriver, 1/4" nut driver, needle-nose pliers. Photograph all hose and wiring connections before disconnecting. Inspect the rubber vacuum hose for cracks before reusing.
• Warranty: 1-year OEM manufacturer warranty against defects. Ships same business day from our warehouse when ordered before cutoff.

Compatibility: Designed for the Carrier PG9MAA036080AFKA gas furnace. Note: OEM part HK06NB123 has been superseded by HK06NB124 as the current factory-authorized replacement — both are covered by this listing. Always verify the W.C. rating printed on your existing switch before ordering. Questions about fitment? Our HVAC parts team confirms compatibility before you buy — no guesswork.