OEM Carrier 1-Pole Contactor 24V 25A for Model PH12NA024000AAAA — Part# HN51KB024

This OEM single-pole contactor is the factory-specified replacement for the Carrier PH12NA024000AAAA heat pump system. The contactor acts as the main high-voltage switching relay in the outdoor unit, controlled by a low-voltage (24V) signal from the thermostat to energize the compressor and condenser fan motor. When the contactor fails, the outdoor unit will not respond to a cooling or heating call — you may hear a buzzing or clicking from the contactor but the compressor and fan will remain off, or the unit may run continuously if the contacts are welded shut.

• Specs: 1-Pole (Single Pole) | 24V AC 50/60Hz Coil | 25 FLA (Full Load Amps) | Definite Purpose Contactor | Factory-matched OEM construction
• OEM vs Generic: This genuine Carrier OEM contactor (HN51KB024) uses silver-alloy contacts rated to exact factory current specifications. Generic aftermarket contactors often use lower-grade contact materials that arc and pit prematurely, leading to repeat failures and potential compressor damage.
• Install Difficulty: 2/5 — Always disconnect power at the disconnect box and verify voltage is absent with a multimeter before beginning. Tools needed: flathead and Phillips screwdrivers, 1/4" nut driver, needle-nose pliers. Photograph all wiring before removing the old contactor. Label each wire prior to disconnecting.
• Warranty: 1-year OEM factory warranty included. In-stock orders ship same business day from our warehouse.

Compatibility: Designed to fit the Carrier PH12NA024000AAAA heat pump. Verify single-pole configuration, 24V coil voltage, and 25 FLA rating on your unit's data plate before ordering. Not sure if this is the right part? Our HVAC parts specialists verify fitment before you buy — contact us today and get your system back up and running fast.