OEM Carrier High & Low Pressure Switch Kit HK02ZA442 / HK02ZB044 for Model PY1REA072074ACWA

This OEM pressure switch kit contains both the high-pressure switch (HK02ZA442) and the low-pressure switch (HK02ZB044) — the factory-specified refrigerant circuit protection components for the Carrier PY1REA072074ACWA packaged rooftop unit. These switches continuously monitor refrigerant pressure on the high and low sides of the refrigeration circuit. When a pressure fault occurs — whether from a refrigerant overcharge, blockage, low charge, or loss of airflow — one or both switches will open, triggering a system lockout to protect the compressor from catastrophic failure. Common symptoms of failure include the unit locking out on a pressure fault code, not cooling despite the blower running, or short-cycling with a compressor trip.

• HK02ZA442 Specs: High Pressure Switch | Opens at 448 PSI | Closes at 327 PSI | Factory OEM tolerance | Replaces HK02ZA439
• HK02ZB044 Specs: Low Pressure Switch | Opens at 7 PSI | Closes at 22 PSI | 50" lead | 24V control circuit | OEM factory-matched
• OEM vs Generic: Genuine Carrier OEM switches are calibrated to exact trip-point tolerances. Generic substitutes frequently drift outside factory spec, leading to nuisance lockouts or — worse — failing to protect the compressor under true fault conditions.
• Install difficulty: 3/5 — Refrigerant circuit work requires EPA 608 certification. Recover refrigerant before disconnecting. Tools needed: manifold gauge set, wire stripper, 1/4" flare fittings, multimeter. Photograph all wiring before removal. Leak-check after reinstallation.
• Warranty: 1-year OEM factory warranty on both switches. Ships same business day from our warehouse.

Compatibility: This kit is designed for the Carrier PY1REA072074ACWA packaged rooftop unit. Verify refrigerant type and pressure ratings on your unit data plate before ordering. Bundle pricing applies when both part numbers are purchased together. Questions about fitment? Our HVAC parts specialists verify compatibility before you order — in stock and ships today.