OEM Carrier Pressure Switch HK02ZB038 for Model PY1PNA042100ADBA

This OEM pressure switch (part number HK02ZB038) is the factory-specified replacement for the Carrier PY1PNA042100ADBA packaged unit. The pressure switch monitors the negative pressure (vacuum) created by the inducer motor to confirm that the flue is properly venting before allowing ignition to proceed. When this switch fails — whether stuck open or stuck closed — the control board will not advance past the inducer stage, leaving the system in a no-heat lockout. Common symptoms include the inducer motor running continuously with no ignition, intermittent heating failures in cold weather, or a fault code indicating a pressure switch fault.

• Specs: 22" W.C. close pressure | 7" W.C. open pressure | 50" lead wire | Factory-matched setpoints for PY1PNA042100ADBA inducer assembly
• OEM vs Generic: This is a genuine OEM Carrier part manufactured to factory setpoint tolerances. Generic aftermarket switches can carry ±15% pressure tolerances, causing nuisance lockouts or — worse — allowing ignition under unsafe venting conditions.
• Install difficulty: 2/5 — Shut off power at the disconnect before beginning. Tools needed: 1/4" nut driver, needle-nose pliers, and a manometer if re-verifying switch setpoint. Swap the two hose connections and single wire harness plug. Always check hoses and ports for cracks or blockage before installing the new switch.
• Warranty: 1-year OEM factory warranty against manufacturing defects. Ships same business day from our warehouse.

Compatibility: Direct OEM replacement for Carrier model PY1PNA042100ADBA packaged unit. Verify the 22# close / 7# open specification against your unit's existing switch label before ordering. Our HVAC parts specialists are available to confirm fitment — contact us before you order if you have any questions.