OEM Carrier Transformer 120V–24V 40VA for Model YAC36100YAC101

This is the factory OEM replacement transformer (part number HT01BD201) for the Carrier YAC36100YAC101 packaged unit. The transformer steps line voltage (120V) down to 24V AC to power the entire low-voltage control circuit — including the thermostat, contactor coil, and control board. When this part fails, nothing responds: the thermostat goes blank, the system won't call for heating or cooling, and diagnostic LEDs on the board may go dark. It is often the first component to check when the entire unit appears dead despite confirmed line voltage at the disconnect.

• Specs: Primary 120V AC | Secondary 24V AC | 40VA rated | Encapsulated core construction | Compatible with R-410A control circuits
• OEM vs Generic: This OEM unit (HT01BD201) is factory-wound and encapsulated to Carrier's exact VA and voltage tolerance specifications. Generic transformers frequently under-rate their VA output, causing overheating, nuisance tripping, and premature failure — especially under full control-circuit load.
• Install Difficulty: 2/5 — Shut off all power at the disconnect and breaker before starting. Tools needed: flat-head and Phillips screwdrivers, needle-nose pliers, multimeter (verify 0V before touching wires). Photograph all low-voltage wiring before disconnecting. Swap wire-for-wire and confirm 24V output with a meter before reassembling panels.
• Warranty: 1-year OEM factory warranty. In-stock and ships same business day from our warehouse.

Compatibility: Engineered as a direct OEM replacement for Carrier model YAC36100YAC101 packaged units. Verify primary input voltage and VA rating on your unit's data plate before ordering. Not sure it fits? Our HVAC parts specialists confirm fitment at no charge — just reach out before you order.