OEM Carrier 40VA Control Transformer for Model C50A405063

This OEM control transformer (part# HT01BD702) is the factory-specified replacement for the Carrier C50A405063 commercial rooftop unit. The transformer steps down 120V primary voltage to the 24V secondary signal required to power your thermostat, control board, contactors, and all low-voltage control circuits. When this component fails, the entire control system goes dark — the thermostat loses power, no calls for heating or cooling are processed, and the unit becomes completely unresponsive. A blown fuse or tripped breaker that keeps returning is often the first sign of transformer failure.

• Specs: 40VA rating | 120V primary / 24V secondary | Factory-matched OEM design | Class 2 transformer | Compatible with standard 24V control wiring
• OEM vs Generic: The OEM HT01BD702 transformer is wound to exact factory VA tolerance, ensuring stable 24V output under full control load. Generic units are often undersized or poorly regulated, causing nuisance lockouts and premature control board failure.
• Install difficulty: 2/5 — Disconnect all power before servicing. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter (verify 24V output after install). Always label low-voltage wires before disconnecting and check for a shorted load that may have caused the original failure.
• Warranty: 1-year OEM factory warranty. In-stock and ships same business day from our warehouse.

Compatibility: Engineered specifically for the Carrier C50A405063 commercial rooftop packaged unit. Confirm your unit's control voltage and VA requirements on the data plate before ordering. Not sure it's the right part? Our HVAC parts specialists verify fitment before you buy — order with confidence and get your system back online fast.