OEM Carrier 40VA Control Transformer for Model C48A502561

This OEM replacement transformer (part# HT01BD236) is the factory-specified control transformer for the Carrier C48A502561 packaged unit. The transformer steps down line voltage (120V) to the 24V signal used by your thermostat, contactor coil, control board, and all other low-voltage components. When the transformer fails, the entire control circuit goes dead — your thermostat goes blank, the system won't respond to any calls for heating or cooling, and no safety or fault codes will display. A failed transformer is often mistaken for a thermostat or control board issue, making correct diagnosis essential before replacing more expensive components.

• Specs: 40VA rating | 120V primary input | 24V secondary output | Factory-matched winding and impedance | Replaces OEM part number HT01BD236
• OEM vs Generic: This is a genuine Carrier OEM transformer wound to exact factory VA and voltage tolerances. Generic transformers may be under-rated for VA load, causing overheating, nuisance tripping of the internal thermal fuse, or premature failure under full control-circuit demand.
• Install difficulty: 2/5 — Shut off all power at the disconnect and breaker before beginning. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter. Verify secondary output reads 24–28V AC after installation before restoring full power. Photograph existing wiring before disconnecting.
• Warranty: 1-year OEM factory warranty against defects. In stock and ships same business day from our climate-controlled warehouse.

Compatibility: Engineered specifically for the Carrier C48A502561 packaged unit. Always verify primary voltage and VA rating on your unit's data plate before ordering. If you're unsure of fitment, our HVAC parts specialists are available to confirm compatibility before you purchase. Order today for same-day shipping.