OEM Carrier 40VA Control Transformer HT01BD236 for Model C50A302751

This is the factory OEM replacement transformer for the Carrier C50A302751 commercial packaged unit. The transformer steps down 120V line voltage to the 24V signal required by your thermostat, control board, contactor coil, and all low-voltage control circuit components. When this part fails, the entire control circuit goes dark — the thermostat loses power, the system won't respond to any call for heating or cooling, and no fault codes will appear because the board itself has no power to report them.

• Specs: 40VA rated | Primary: 120V | Secondary: 24V | OEM part number HT01BD236 | Factory-matched windings for stable, clean 24V output
• OEM vs Generic: OEM transformers are wound to exact VA and voltage tolerances for Carrier control circuits. Undersized or off-tolerance generic transformers can trip thermal overloads under normal load, causing intermittent lockouts and difficult-to-diagnose failures.
• Install difficulty: 2/5 — Disconnect power at the breaker before beginning. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter to verify 24V output after install. Label or photograph all low-voltage wiring before disconnecting from old transformer terminals.
• Warranty: 1-year OEM factory warranty. In-stock units ship same business day from our warehouse.

Compatibility: Designed specifically for the Carrier C50A302751 commercial rooftop/packaged unit. Verify your existing transformer's VA rating and primary/secondary voltages on the unit data plate before ordering. If your thermostat screen is blank and all fuses check good, this transformer is the most likely cause. Our fitment specialists are available to confirm compatibility before you order.