OEM Carrier High & Low Pressure Switch Set for Model PH14NB018000AAAA

This OEM pressure switch listing covers both the high pressure switch (312926-252) and low pressure switch (312926-258) — the factory-specified refrigerant circuit protection components for the Carrier PH14NB018000AAAA heat pump system. These switches continuously monitor refrigerant pressure on both the high and low sides of the refrigerant circuit. When pressure drifts outside safe operating limits — due to refrigerant loss, a blocked condenser coil, or a failing metering device — the corresponding switch opens, triggering a system lockout to prevent compressor damage. Common symptoms of failure include the unit going into lockout shortly after startup, fault codes indicating low or high pressure trips, or a system that short-cycles and will not resume normal operation.

• Specs: High Pressure Switch: OEM Part 312926-252 | Low Pressure Switch: OEM Part 312926-258 | Factory-calibrated trip points matched to PH14NB018000AAAA refrigerant circuit design | Spade terminal connections
• OEM vs Generic: OEM switches use factory-calibrated pressure set points. Aftermarket alternatives often carry wider tolerances that can allow the compressor to operate outside safe pressure bands, shortening its service life significantly.
• Install Difficulty: 3/5 — Refrigerant circuit work requires an EPA 608-certified technician. Tools needed: manifold gauge set, needle-nose pliers, multimeter for continuity check, and torque wrench. Always recover refrigerant before disconnecting any pressure switch on the high side.
• Warranty: 1-year OEM factory warranty on both switches. Orders ship same business day from our warehouse when placed before 3 PM local time.

Compatibility: Both switches are direct OEM replacements for the Carrier PH14NB018000AAAA heat pump. Verify your existing switch part numbers against 312926-252 (high) and 312926-258 (low) from your unit's wiring diagram or data plate before ordering. Not sure which switch you need? Our HVAC parts specialists can confirm fitment — contact us before you order.