OEM Carrier Control Transformer 40VA for Model C50A802564

This OEM replacement transformer (part# HT01BD702) is the factory-specified step-down transformer for the Carrier C50A802564 packaged unit. The transformer steps down 120V line voltage to the 24V AC signal that powers your thermostat, control board, contactor coil, and all low-voltage safety circuits. When this component fails, the entire control circuit goes dark — the thermostat loses power, the system won't respond to any calls for heating or cooling, and in many cases the unit appears completely dead despite line voltage being present.

• Specs: 40VA rated | 120V primary / 24V secondary | Class 2 transformer | OEM part number HT01BD702 | Factory-matched output tolerance for reliable low-voltage operation
• OEM vs Generic: This OEM unit is wound to Carrier's exact VA rating and insulation class. Undersized or off-spec generic transformers can overheat under normal load, tripping thermal cutoffs repeatedly and shortening the life of downstream controls.
• Install difficulty: 2/5 — Disconnect power at the breaker before beginning. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter (to confirm 24V output after install). Label or photograph all low-voltage wiring before disconnecting. Swap primary and secondary leads carefully — reversing them will damage the board.
• Warranty: 1-year OEM factory warranty against defects. Orders placed by 3PM local time ship same business day from our climate-controlled warehouse.

Compatibility: Engineered for the Carrier C50A802564 commercial rooftop/packaged unit. Always verify your existing transformer's VA rating and primary/secondary voltages on the unit data plate or wiring diagram before ordering. Our fitment specialists are available to confirm compatibility before you purchase — ships same day, so your system is back online fast.