OEM Carrier Transformer 40VA 120V/24V for Model C50A505063

This is the factory-original replacement transformer (OEM part number HT01BD702) for the Carrier C50A505063 commercial rooftop unit. The control transformer steps down line voltage from 120V to 24V AC to power the low-voltage control circuit — including the thermostat, contactor coils, and all safety switches. When this transformer fails, the entire control circuit goes dead: your thermostat goes blank, the system stops responding to calls for heating or cooling, and no contactors or relays will energize. It is one of the first components to check when absolutely nothing responds.

• Specs: 40VA rating | Primary: 120V AC | Secondary: 24V AC | Class 2 output | Direct OEM replacement for part number HT01BD702 | Factory-matched insulation class and VA rating
• OEM vs Generic: OEM transformers are wound and insulated to Carrier's exact VA and thermal specifications. Undersized or generic transformers can overheat under full control-circuit load, tripping the internal thermal cutout and causing intermittent lockouts — a notoriously difficult fault to diagnose.
• Install difficulty: 2/5 — Shut off all power at the disconnect and breaker before beginning. Tools needed: flathead and Phillips screwdrivers, wire strippers, multimeter, and wire nuts or terminal connectors. Label all low-voltage wires before removing the old unit. Confirm 24V output with a multimeter before restoring full power.
• Warranty: 1-year OEM factory warranty against defects in materials and workmanship. In-stock units ship the same business day from our warehouse.

Compatibility: Designed for the Carrier C50A505063 commercial rooftop packaged unit. Verify your existing transformer's VA rating, primary voltage, and mounting configuration against your unit's data plate before ordering. Our HVAC parts specialists are available to confirm fitment — reach out before you order if you have any questions. Order now and your part ships today.