OEM Carrier Transformer 120V–24V 40VA for Model PH4GNXB36000AA

This OEM step-down transformer (part number HT01BD242) is the factory-specified replacement for the Carrier PH4GNXB36000AA packaged unit. The transformer converts 120V line voltage to 24V AC, powering the entire low-voltage control circuit — including the thermostat, contactor coil, and control board. When this part fails, the system goes completely unresponsive: the thermostat goes dark, the contactor won't pull in, and no heating or cooling cycle can initiate.

• Specs: Primary Voltage: 120V AC | Secondary Voltage: 24V AC | VA Rating: 40VA | OEM Part Number: HT01BD242 | Factory-matched winding tolerance
• OEM vs Generic: This OEM transformer is wound to exact factory specifications for the Carrier PH4GNXB36000AA, ensuring precise 24V output under full load. Generic transformers often run outside ±5% voltage tolerance, which can cause nuisance lockouts or premature control board failure.
• Install Difficulty: 2/5 — Shut off all power to the unit before beginning. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter (to verify 24V output after install). Photograph all wiring connections before removal. Wire nuts or terminal connectors may be required depending on installation.
• Warranty: 1-year OEM factory warranty. In-stock and ships same business day from our warehouse.

Compatibility: Designed for the Carrier PH4GNXB36000AA packaged unit. Always verify primary input voltage and VA 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 order — reach out before checkout.