OEM Carrier Transformer 120V/24V 40VA for Model 09DE054C510

This is the factory OEM replacement transformer (part number HT01BC208) for the Carrier 09DE054C510 unit. The transformer steps down line voltage from 120V AC (primary) to 24V AC (secondary), powering the entire low-voltage control circuit — including the thermostat, control board, contactor coil, and all safety switches. When this transformer fails, the result is a completely unresponsive system: the thermostat goes blank, the unit won't call for heating or cooling, and the control board loses power entirely. A failed transformer is one of the most common causes of a system that appears completely dead at the stat.

• Specs: 120V AC primary | 24V AC secondary | 40VA rated | Single-phase | Factory-matched electrical ratings for the 09DE054C510 control circuit
• OEM vs Generic: This OEM unit from Carrier is wound and rated to exact factory specifications. Generic transformers often carry imprecise VA ratings and thinner windings that overheat under full control-circuit load, leading to premature failure and nuisance tripped breakers.
• Install Difficulty: 2/5 — Shut off all power at the disconnect and breaker before starting. Tools needed: flathead and Phillips screwdrivers, multimeter (to verify 24V output post-install), wire stripper, and electrical tape or wire nuts. Always confirm transformer polarity and verify no short on the secondary before energizing.
• Warranty: 1-year OEM factory warranty. In-stock and ships same business day from our warehouse.

Compatibility: Engineered specifically for the Carrier 09DE054C510. Always verify your unit's control circuit voltage and VA draw against your data plate before ordering. If your system uses additional accessories (humidifiers, UV lights, zoning boards) drawing secondary power, confirm the 40VA rating meets your total load. Our fitment team is available to verify compatibility before you order — same-day shipping on all in-stock parts.