OEM Carrier High & Low Pressure Switch Kit — 312926-252 & 312926-258 for Model PH13NB04900GAAAA

These two OEM Carrier pressure switches are the factory-specified replacements for the Carrier PH13NB04900GAAAA heat pump. The High Pressure Switch (312926-252, 670/470 PSI) monitors the refrigerant circuit on the high side and cuts power to the compressor if pressure exceeds the safe operating threshold — protecting the compressor from catastrophic over-pressurization. The Low Pressure Switch (312926-258, 55/23 PSI) guards against low-side pressure drop caused by refrigerant loss, a frozen coil, or a restricted metering device, opening the circuit before the compressor runs in a starved condition. When either switch fails, the system typically presents as a compressor short-cycle, nuisance high- or low-pressure fault codes, or a complete no-cooling/no-heating lockout that won't clear without a manual reset.

• Specs — High Pressure Switch (312926-252): Cut-out 670 PSI | Cut-in 470 PSI | OEM Carrier Factory Authorized Part | Replaces legacy P/N 312926252
• Specs — Low Pressure Switch (312926-258): Cut-out 55 PSI | Cut-in 23 PSI | OEM Carrier Factory Authorized Part | Sensata/PS80-02 platform
• OEM vs Generic: OEM pressure switches are factory-calibrated to exact cut-in/cut-out setpoints. Aftermarket units frequently carry ±10–15% tolerances on trip pressure, risking nuisance trips or — worse — failure to protect the compressor under a true fault condition.
• Install difficulty: 3/5 — Refrigerant circuit work requires an EPA 608 certified technician. Tools needed: manifold gauge set, refrigerant recovery equipment, wire strippers, multimeter. Always recover refrigerant before disconnecting the high-side switch; the low-side switch may be changed with the system in vacuum on some configurations. Photograph all wiring before removal.
• Warranty: 1-year OEM manufacturer warranty. Ships same business day from our warehouse when ordered before cutoff.

Compatibility: Engineered for the Carrier PH13NB04900GAAAA heat pump. Verify refrigerant type and system tonnage on your unit's data plate before ordering. Not sure if both switches need replacement? Our HVAC parts specialists can verify fitment and help you diagnose which switch has failed before you buy. Questions? Contact us — we confirm fitment on every order.