OEM Carrier 40VA Control Transformer 120V–24V for Model 09DE084C510

This OEM replacement control transformer (part HT01BC208) is the factory-specified unit for the Carrier 09DE084C510 HVAC system. The transformer steps down line voltage from 120V to the 24V needed to power the low-voltage control circuit — including the thermostat, contactor coil, and control board. When the transformer fails, the entire control circuit goes dead: the thermostat goes blank, the system will not respond to any commands, and no heating or cooling can occur.

• Specs: 120V primary | 24V secondary | 40VA rating | Factory-matched construction for reliable low-voltage output
• OEM vs Generic: This OEM unit is wound to Carrier's exact VA and voltage tolerances. Generic transformers may under-deliver on VA capacity, causing nuisance tripping or premature failure when contactor coils draw peak current on startup.
• Install difficulty: 2/5 — Always disconnect power at the breaker before replacing. Tools needed: flathead and Phillips screwdrivers, wire nuts or terminal connectors, multimeter (to verify 24V output post-install). Photograph existing wiring before disconnecting any leads.
• Warranty: 1-year OEM factory warranty. In-stock and ships same business day from our warehouse.

Compatibility: Designed for the Carrier 09DE084C510 system. Confirm your unit's control voltage (24V) and VA draw on the data plate or wiring diagram before ordering. Not sure it fits? Our HVAC parts specialists verify fitment before you buy — contact us anytime.