OEM Carrier High Pressure Switch HK02ZA395 / HK02ZB044 for Model PH1PNB048000AAAA

This is the factory OEM high pressure switch for the Carrier PH1PNB048000AAAA heat pump package unit. The high pressure switch is a critical refrigerant-circuit safety device: it monitors system head pressure and opens the circuit when pressure exceeds the rated cutout threshold, protecting the compressor from catastrophic damage caused by refrigerant overcharge, restricted airflow, or a failing condenser fan motor. When this switch fails or trips without resetting, the unit will typically lock out on a high-pressure fault, deliver no cooling or heating, and may display a fault code on the thermostat or control board. This listing covers both OEM part numbers applicable to this model: HK02ZA395 (High Pressure Switch, opens at 395 PSI / closes at 295 PSI) and HK02ZB044 (Pressure Switch, opens at 7 PSI / closes at 22 PSI — low-side companion switch).

• Specs — HK02ZA395: Opens at 395 PSI | Closes at 295 PSI | 240 VAC rated | 1/8" NPT male fitting | SPST normally-closed | Factory-matched Sensata/RCD PS80 series
• OEM vs Generic: OEM Carrier pressure switches are manufactured to exact factory cutout tolerances (±1–2 PSI). Aftermarket substitutes frequently exhibit wider tolerance bands, which can lead to nuisance trips, compressor short-cycling, or — more dangerously — failure to open under a true high-pressure event, risking compressor failure.
• Install Difficulty: 3/5 — Refrigerant circuit work requires EPA 608 certification. Always recover refrigerant and de-energize the unit before replacing a high-side pressure switch. Tools needed: manifold gauge set, 1/4" or 3/8" flare wrench, multimeter, lockout/tagout equipment. Verify the new switch seats with no leaks before re-energizing.
• Warranty: 1-year OEM Carrier factory warranty. In-stock and ships same business day from our NationalHVACParts.com warehouse.

Compatibility: Engineered as a direct OEM replacement for Carrier model PH1PNB048000AAAA (4-ton packaged heat pump unit). Always confirm the part number stamped on your existing switch before ordering, as pressure switch ratings vary by refrigerant circuit configuration and tonnage. Have questions about fitment? Our team verifies compatibility before you order — contact us today and ship with confidence.