OEM Carrier Low Pressure Switch 55-23# (312926-258) for Model PH15NB03700GBBAA

This is the genuine OEM low pressure switch (part number 312926-258), the factory-specified replacement for the Carrier PH15NB03700GBBAA heat pump. The low pressure switch continuously monitors refrigerant pressure on the suction side of the system. When pressure drops below the factory-set threshold — due to low refrigerant charge, a blocked metering device, or a failing TXV — this switch opens the circuit and shuts down the compressor to prevent catastrophic damage. Common symptoms of a failed low pressure switch include the system going into lockout shortly after startup, error codes indicating a low pressure fault, or the compressor refusing to energize at all.

• Specs: 55-23# pressure rating | Factory-calibrated setpoints | Brass inlet connector | Precision-machined diaphragm | Pre-wired color-coded leads for direct swap
• OEM vs Generic: This is a genuine Carrier Factory Authorized Part (FAP), manufactured to exact OEM tolerances. Aftermarket switches often use inferior diaphragm materials and drift off calibration over time, risking nuisance trips or — worse — compressor damage from undetected low pressure events.
• Install difficulty: 2/5 — Always recover refrigerant per EPA Section 608 before disconnecting pressure switches. Tools needed: refrigerant recovery machine, manifold gauge set, wire terminals or crimping tool, multimeter for continuity verification post-install. Photograph all wiring before removal.
• Warranty: 1-year OEM factory warranty against defects. In stock and ships same business day from our NationalHVACParts.com warehouse.

Compatibility: Direct OEM replacement for Carrier model PH15NB03700GBBAA heat pump systems. Verify your existing switch's pressure rating (55-23#) against your unit's data plate or wiring diagram before ordering. Our technical team is available to confirm fitment — contact us before you buy if you have any questions.