OEM Carrier 40VA Control Transformer HT01BD702 for Model C48A503564

This is the factory OEM replacement transformer (part number HT01BD702) designed specifically for the Carrier C48A503564 packaged unit. The transformer steps down 120V line voltage to 24V AC to power the entire low-voltage control circuit — including the thermostat, contactor coil, and control board. When this transformer fails, nothing works: the thermostat goes blank, the system won't respond to any call for heating or cooling, and you may measure zero voltage on the secondary side of the control board. A blown transformer is often the first sign of a shorted wire or failed component downstream, so always inspect the control circuit before replacing.

• Specs: 40VA rated | Primary: 120V AC | Secondary: 24V AC | OEM part number HT01BD702 | Factory-matched for Carrier C48A503564 packaged units
• OEM vs Generic: This OEM transformer is wound to exact factory VA and voltage specifications. Generic transformers frequently run undersized VA ratings that cause overheating, nuisance tripping, and premature failure — especially under full control-circuit load.
• Install difficulty: 2/5 — Disconnect power at the disconnect box before beginning. Tools needed: flathead and Phillips screwdrivers, multimeter, wire nuts or spade connectors. Always verify zero voltage with a meter before touching any wiring. Note primary and secondary wire colors before disconnecting.
• Warranty: 1-year OEM factory warranty against defects. Ships same business day from our warehouse when ordered before 3 PM local time.

Compatibility: Engineered as the direct OEM replacement for Carrier model C48A503564 packaged units. Verify your existing transformer's VA rating and primary/secondary voltages on the unit data plate before ordering. If you're unsure of fitment, our HVAC parts specialists are available to confirm compatibility before you buy — same-day shipping available on all in-stock OEM parts.