OEM Carrier Pressure Switch 22 PSI Close / 7 PSI Open for Model PH12NA03000GABAA

This is the OEM factory-specified pressure switch (part number HK02ZB038) for the Carrier PH12NA03000GABAA packaged unit. The pressure switch monitors inducer draft pressure to confirm safe venting conditions before allowing the ignition sequence to proceed. When it fails or loses calibration, the furnace or packaged unit will lock out before ignition — commonly presenting as a no-heat call with a pressure switch fault code on the control board. A faulty inducer motor, blocked condensate drain, or cracked hose can also trigger this switch, so always inspect those components before replacing the switch itself.

• Specs: Close set point: 22" W.C. | Open set point: 7" W.C. | Lead length: 50" | SPST normally-open configuration | OEM part number: HK02ZB038
• OEM vs Generic: This is the genuine Carrier OEM part, factory-calibrated to exact W.C. set points. Aftermarket switches often carry wider tolerance ranges, risking nuisance lockouts or — worse — permitting ignition under unsafe draft conditions.
• Install difficulty: 2/5 — Turn off power at the disconnect before beginning. Tools needed: 1/4" nut driver, flathead screwdriver, manometer (for verification). Disconnect the hose port and two wiring leads, swap the switch, reconnect, and cycle the unit. Always inspect the rubber pressure hose for cracks or blockages while the panel is open.
• Warranty: 1-year OEM manufacturer warranty against defects. Ships same business day from our warehouse when ordered before 3 PM local time.

Compatibility: Direct OEM replacement for Carrier PH12NA03000GABAA packaged units. Verify your unit's existing switch set points and lead length against your data plate before ordering. Our fitment team is available to confirm compatibility — just reach out before you buy. In stock and ready to ship today.