OEM Carrier 40VA Control Transformer HT01BD702 for Model C48A202564

This OEM control transformer (part# HT01BD702) is the factory-specified replacement for the Carrier C48A202564 packaged unit. The transformer steps down 120V line voltage to the 24V signal that powers your thermostat, contactor coil, control board, and all low-voltage control circuits. When it fails, the entire control system goes dark — the thermostat loses power, the unit won't respond to any call for heating or cooling, and no error codes are produced because the board itself has no power. A failed transformer is often misdiagnosed as a thermostat or control board failure, making correct identification critical before replacing more expensive components.

• Specs: 40VA rating | Primary voltage: 120V | Secondary voltage: 24V | OEM part number HT01BD702 | Factory-matched output tolerance for reliable low-voltage control
• OEM vs Generic: This is the genuine Carrier OEM transformer, wound and rated to exact factory specifications. Generic transformers often use undersized cores that overheat under full VA load, leading to premature failure and potential damage to connected control boards.
• Install difficulty: 2/5 — Disconnect power at the breaker and verify zero voltage with a multimeter before servicing. Tools needed: flathead and Phillips screwdrivers, wire nuts or terminal connectors, multimeter. Note wire colors and terminal labels before disconnecting. Confirm VA and voltage ratings match your unit's data plate.
• Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Fits Carrier model C48A202564 packaged unit. Always verify the 120V primary and 24V secondary voltage ratings and the 40VA capacity on your unit's data plate before ordering. Our parts specialists are available to confirm fitment — reach out before you order if you have any questions.