OEM Carrier Transformer 120V–24V 40VA for Model YAC36100YAC302

This OEM step-down transformer (part number HT01BD201) is the factory-specified replacement for the Carrier YAC36100YAC302 unit. The transformer converts incoming 120V line voltage down to the 24V signal voltage required to power the entire low-voltage control circuit — including the thermostat, contactor coil, and all safety safeties. When this transformer fails, nothing works: the thermostat goes dark, the system refuses to respond to any calls for heating or cooling, and you may find a blown fuse on the control board caused by a shorted secondary winding.

• Specs: Primary voltage: 120V AC | Secondary voltage: 24V AC | VA rating: 40VA | Factory OEM part number: HT01BD201 | Carrier-matched terminals for direct plug-in replacement
• OEM vs Generic: This is the exact factory transformer Carrier installs at the production line. OEM units are wound to precise VA tolerances, protecting downstream components. Generic transformers frequently underperform on VA output, causing nuisance lockouts and premature contactor coil burnout.
• Install difficulty: 2/5 — Disconnect all power before beginning. Tools needed: flathead and Phillips screwdrivers, multimeter (to verify 24V output after install), wire nuts or spade connectors. Label all wiring before disconnecting and verify polarity on the secondary side before powering up.
• Warranty: 1-year OEM factory warranty. In-stock and ships same business day from our warehouse.

Compatibility: Directly fits Carrier model YAC36100YAC302. Always confirm your unit's control board input voltage and VA requirement on the data plate or wiring diagram before ordering. Have questions about fitment? Our HVAC parts specialists verify compatibility before you buy — contact us today and get your system back online fast.