OEM Carrier 40VA Control Transformer HT01BD702 for Model C50A405064

This OEM step-down transformer is the factory-specified replacement for the Carrier C50A405064 commercial rooftop packaged unit. The transformer steps voltage down from 120V primary to 24V secondary, powering the entire low-voltage control circuit — including the thermostat, contactor coils, and control board. When this component fails, nothing in the system responds: the thermostat goes blank, the unit won't start, and no call for heating or cooling is processed. It is often the first component to inspect when a unit appears completely unresponsive.

• Specs: 40VA rating | 120V primary / 24V secondary | OEM Part Number HT01BD702 | Factory-matched for Carrier C50A405064 commercial rooftop units
• OEM vs Generic: This is a genuine OEM Carrier transformer built to exact VA and voltage tolerances. Generic transformers can vary in VA output, leading to brownouts in the control circuit, nuisance lockouts, and premature failure of downstream control boards and contactors.
• Install difficulty: 2/5 — Shut off all power to the unit at the disconnect before beginning. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter. Label or photograph all low-voltage wiring connections before disconnecting. Verify 24V output across secondary terminals after installation before restoring full power.
• Warranty: 1-year OEM factory warranty against defects. In-stock and ships same business day from our warehouse.

Compatibility: Designed for the Carrier C50A405064 commercial rooftop packaged unit. Confirm primary voltage (120V) and VA rating on your existing transformer's label before ordering. If your unit runs a 208V or 240V primary circuit, verify your specific wiring configuration. Our HVAC parts specialists are available to confirm fitment before you order — don't let a dead control circuit slow down your building.