OEM Carrier 1-Pole Contactor 24V 25 Amp — HN51KB024 for Model PH12NA024000ADAA

This is the factory-specified OEM single-pole contactor for the Carrier PH12NA024000ADAA packaged unit. The contactor is the high-voltage switching relay that receives a 24V signal from your thermostat and closes the circuit to energize the compressor and/or fan motor. When the contactor fails — through burned contacts, a welded coil, or a pitted switching surface — the system will either fail to start entirely, run continuously without shutting off, or make a loud buzzing/humming noise with no cooling output. This is one of the most common failure points in any residential or light-commercial HVAC system and is a straightforward DIY replacement.

• Specs: 1-Pole | 24V 50/60Hz Coil | 25 FLA (Full Load Amps) | OEM Part# HN51KB024 | Factory tolerance-matched contacts for reliable pull-in and drop-out
• OEM vs Generic: OEM Carrier contactors use factory-spec contact materials and coil windings calibrated to exact pull-in voltage thresholds. Generic contactors may have looser coil tolerances, leading to chatter, premature contact pitting, and shortened service life — especially during high-demand summer operation.
• Install difficulty: 2/5 — Always shut off power at the disconnect and the breaker before beginning. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter (to verify 24V coil signal). Photograph all wiring connections before removing the old contactor. Transfer wires one at a time to avoid miswiring.
• Warranty & Shipping: 1-year OEM factory warranty. In stock and ships same business day from our warehouse when ordered before cutoff.

Compatibility: Engineered for the Carrier PH12NA024000ADAA packaged unit. Verify your unit's data plate lists part number HN51KB024 or cross-references a 1-pole, 24V, 25 FLA contactor before ordering. Not sure if this is the right part? Our fitment team will confirm compatibility before you buy — just reach out before placing your order.