OEM Carrier High Pressure Switch (HK02ZA442) for Model PY1RPA072074ACWA

This is the factory OEM high-pressure switch for the Carrier PY1RPA072074ACWA packaged rooftop unit. Operating as the refrigerant circuit's safety sentinel, this switch monitors system discharge-side pressure and opens the control circuit when pressure exceeds a safe threshold — cutting the compressor and preventing catastrophic system damage. When it fails (open-circuit failure), the unit will typically go into a fault lockout without completing a cooling cycle, or nuisance-trip on normal operating pressure. A failed or out-of-calibration high-pressure switch is a leading cause of "no cooling" service calls on commercial rooftop equipment.

• Specs — HK02ZA442 (High Pressure Switch): 448 PSI open / 327 PSI close | SPST normally-closed | Factory-calibrated setpoints | Replaces HK02ZA439
• Companion Part — HK02ZB044 (Low Pressure Switch): 7 PSI open / 22 PSI close | 50" lead wire | Sold separately — ask our team about bundling both switches for a complete pressure-safety service
• OEM vs Generic: Genuine Carrier Factory Authorized Parts are manufactured to exact setpoint tolerances. Aftermarket pressure switches frequently carry ±5–10% calibration variance, which can cause nuisance trips or — more dangerously — fail to open at true high-pressure events, risking compressor damage.
• Install Difficulty: 3/5 — Refrigerant circuit work. System must be isolated before disconnecting the high-side pressure switch. Tools required: manifold gauge set, 1/4" flare fittings, needle-nose pliers, multimeter for continuity check post-install. Recommended for certified HVAC/R technicians. Always verify system pressure is relieved before touching fittings.
• Warranty: 1-year OEM factory warranty. In stock — ships same business day from our warehouse.

Compatibility: Factory-matched for Carrier model PY1RPA072074ACWA packaged rooftop unit. This listing covers the primary high-pressure switch (HK02ZA442). Both HK02ZA442 and companion low-pressure switch HK02ZB044 are stocked and available. Verify your unit's data plate and wiring diagram before ordering — our parts specialists are available to confirm fitment. Order today and receive same-day shipping on all in-stock orders.