OEM Carrier Transformer 120V–24V 40VA for Model PH4GEAA60000AA

This is the factory-specified OEM step-down transformer for the Carrier PH4GEAA60000AA packaged heat pump unit. The transformer is the backbone of your system's low-voltage control circuit, converting 120V line voltage down to 24V AC to power the thermostat, control board, contactor coil, and all accessory relays. When it fails, the entire control circuit goes dark — the thermostat becomes unresponsive, the system will not call for heating or cooling, and no fault codes will appear on the board because there is no power to generate them.

• Specs: Primary: 120V AC | Secondary: 24V AC | Rating: 40VA | OEM Part Number: HT01BD242 | Factory-matched for Carrier PH4GEAA60000AA
• OEM vs Generic: This OEM unit is wound to exact factory VA and voltage tolerances, ensuring stable 24V output even under peak load (e.g., when multiple accessories draw simultaneously). Undersized or off-tolerance generic transformers can cause erratic control board behavior, nuisance lockouts, and premature contactor failure.
• Install Difficulty: 2/5 — Always disconnect power at the breaker and verify zero voltage with a multimeter before touching wiring. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter. Label all low-voltage wires before removal. The transformer mounts to the control box panel with two screws; spade or screw-terminal connections vary by vintage.
• Warranty: 1-year OEM factory warranty on part HT01BD242. Ships same business day from our warehouse when ordered before 3 PM local time.

Compatibility: Engineered as a direct OEM replacement for Carrier model PH4GEAA60000AA packaged heat pump systems. Always confirm your unit's data plate voltage (120V primary) and VA rating before ordering to ensure a precise fit. Have questions about fitment? Our HVAC parts specialists verify compatibility before you buy — reach out via chat or phone.