OEM Carrier 40VA Control Transformer HT01BD702 for Model C50A202564

This OEM step-down transformer (part number HT01BD702) is the factory-specified replacement for the Carrier C50A202564 commercial packaged unit. The transformer converts 120V line voltage to the 24V AC signal that powers the entire control circuit — including the thermostat, contactor coil, gas valve, and control board. When this part fails, absolutely nothing responds: the thermostat goes blank, the system won't call for heating or cooling, and no components energize. It is one of the first components to check when a system appears completely dead despite confirmed line voltage at the unit.

• Specs: 40VA rating | Primary: 120V AC | Secondary: 24V AC | Factory-matched OEM construction | Spade or wire-lead termination per OEM design
• OEM vs Generic: This is the genuine Carrier OEM part — not an aftermarket substitute. OEM transformers are wound and insulated to exact VA and thermal specifications. Undersized or off-tolerance generic transformers can overheat, blow the 3A control fuse repeatedly, or cause erratic board behavior that mimics more expensive failures.
• Install difficulty: 2/5 — Disconnect all power before servicing. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter. Confirm 24V output at secondary terminals after install before re-energizing the full system. Always check for a shorted control circuit 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 and tested for the Carrier C50A202564 commercial rooftop/packaged unit. Always verify your unit's control voltage and VA requirement on the data plate before ordering. Not sure it's the right part? Our HVAC parts specialists confirm fitment before you buy — no guesswork, no costly returns.