OEM Carrier Transformer 40VA 120V–24V for Model C48A503552

This OEM replacement transformer (part number HT01BD236) is the factory-specified control circuit transformer for the Carrier C48A503552 packaged unit. The transformer steps down line voltage (120V) to the 24V low-voltage signal used by your thermostat, control board, contactor coil, and all other safety and switching components. When this part fails, the entire control circuit goes dead — your thermostat loses power, the system won't respond to any call for heating or cooling, and nothing operates. A failed transformer is often mistaken for a thermostat or control board problem, making correct diagnosis critical before replacing more expensive components.

• Specs: 40VA rating | 120V primary input | 24V secondary output | Foot-mount configuration | Factory-matched to Carrier C48A503552 electrical specifications
• OEM vs Generic: This is a genuine OEM Carrier part (HT01BD236), wound and rated to exact factory tolerances. Generic transformers frequently use undersized windings that overheat under full VA load, causing premature failure and potential control board damage.
• Install Difficulty: 2/5 — Disconnect all power at the breaker and confirm zero voltage with a multimeter before beginning. Tools needed: flathead and Phillips screwdrivers, multimeter, wire nuts or spade connectors. Label all low-voltage wiring before disconnecting. Verify fuse integrity on the secondary circuit before condemning the transformer.
• Warranty: 1-year OEM factory warranty. In-stock and ships same business day from our warehouse.

Compatibility: Engineered specifically for the Carrier C48A503552 packaged unit. Always confirm your unit's data plate voltage requirements match this transformer's 120V/24V 40VA specification before ordering. Our HVAC parts specialists are available to verify fitment — order with confidence and get your system back online fast.