OEM Carrier 40VA Control Transformer HT01BD702 for Model C50A203064

This OEM step-down transformer (part number HT01BD702) is the factory-specified replacement for the Carrier C50A203064 commercial packaged unit. The transformer converts 120V line voltage to the 24V AC signal that powers your thermostat, control board, contactor coil, and every other low-voltage component in the system. When it fails, the entire control circuit goes dark — nothing responds, the thermostat goes blank, and the unit will not start under any call for heating or cooling.

• Specs: 40VA rating | Primary: 120V | Secondary: 24V AC | Class 2 control circuit transformer | OEM part number HT01BD702
• OEM vs Generic: This is the genuine Carrier OEM transformer, wound and rated to exact factory specifications. Generic replacements often carry undersized VA ratings that overload under peak demand, blowing fuses or damaging downstream boards.
• Install difficulty: 2/5 — Shut off all power to the unit before starting. Tools needed: flathead and Phillips screwdrivers, multimeter, wire nuts or spade connectors. Always verify 0V at the transformer terminals with your meter before touching wires. Label all low-voltage connections before disconnecting.
• Warranty: 1-year OEM factory warranty. Ships same business day from our warehouse when ordered before cutoff.

Compatibility: Direct OEM replacement for Carrier C50A203064 commercial rooftop/packaged units. Verify your existing transformer's primary voltage, secondary voltage, and VA rating against your unit's data plate before ordering. Need fitment confirmation? Our HVAC parts specialists verify compatibility before you buy — reach out before placing your order.