OEM Carrier High Pressure Switch HK02ZA442 for Model PY1REA036074ABWA

This OEM high pressure switch (part number HK02ZA442) is the factory-specified replacement for the Carrier PY1REA036074ABWA packaged unit. The pressure switch monitors the inducer assembly and proves that adequate airflow and draft pressure are established before allowing the ignition sequence to proceed. When the switch fails — either stuck open or stuck closed — the control board cannot verify safe combustion conditions, resulting in a no-heat fault, repeated ignition lockout, or a fault code pointing to inducer or pressure switch failure. The companion low-pressure switch for this platform is HK02ZB044; both switches work in tandem to fully prove the heat exchanger pressure envelope.

• Specs: 24V control circuit | Opens at 7" W.C. | Closes at 22" W.C. | 50" lead wires | OEM part number HK02ZA442 (high pressure); see also HK02ZB044 (low pressure)
• OEM vs Generic: This is a genuine Carrier OEM switch — factory-matched to exact W.C. setpoints and design life testing. Aftermarket switches often carry ±15% pressure tolerances, which can cause nuisance lockouts or, worse, fail to detect a blocked flue condition.
• Install Difficulty: 2/5 — Power down and confirm inducer is off before disconnecting leads. Tools needed: 1/4" nut driver, needle-nose pliers, and a manometer to verify setpoints post-install. Photograph existing wiring before removal. Replace both switches (HK02ZA442 + HK02ZB044) together if either has failed to avoid a repeat service call.
• Warranty: 1-year OEM factory warranty. Ships same business day from our warehouse.

Compatibility: Engineered for Carrier model PY1REA036074ABWA packaged units. Always verify the W.C. rating and lead length stamped on your existing switch before ordering. Our technical team is available to confirm fitment — reach out before you order if you have any questions.