OEM Carrier High & Low Pressure Switch Kit (HK02ZA442 + HK02ZB044) for Model PY1RPA036074ABWB

This factory-matched OEM pressure switch kit includes both the high pressure switch (HK02ZA442) and the low pressure switch (HK02ZB044) — the two refrigerant circuit safety switches specified for the Carrier PY1RPA036074ABWB packaged heat pump unit. Together, these switches monitor refrigerant pressure on the high and low sides of the refrigerant circuit and shut the compressor down before a damaging over- or under-pressure condition can occur. Symptoms of failure include system lockout with a pressure fault code, compressor short-cycling, nuisance trips on a hot day, or a unit that won't cool despite the thermostat calling. Replacing both switches at the same service call eliminates repeat trips and ensures both safety circuits are factory-calibrated.

• Specs — HK02ZA442 (High Pressure): 448 PSI open / 327 PSI close | SPST N.C. | Factory Authorized Part | Replaces HK02ZA439
• Specs — HK02ZB044 (Low Pressure): 7 PSI open / 22 PSI close | 50" lead wires | 24V | SPST N.C. | OEM Carrier/Bryant/Payne
• OEM vs Generic: OEM switches hold exact factory trip points. Off-brand units can drift ±10–15% on setpoints, risking compressor damage from unchecked high-side pressure or running the system in a low-charge condition.
• Install difficulty: 3/5 — Recover refrigerant charge before disconnecting high-side switch per EPA 608 regulations. Tools needed: manifold gauge set, recovery machine, torque wrench, wire crimpers, multimeter. Always confirm replacement trip points match the unit's data plate before re-commissioning. Low-side switch can often be swapped on low-pressure side with minimal refrigerant loss using a Schrader valve core tool.
• Warranty: 1-year OEM factory warranty on both parts. Ships same business day from our warehouse.

Compatibility: Engineered specifically for the Carrier PY1RPA036074ABWB packaged rooftop/heat pump unit. Verify both part numbers against your unit's wiring diagram and service literature before ordering. Not sure which switch failed? Our HVAC-certified team can help you confirm fitment and diagnose by fault code — contact us before you order.