OEM Carrier Transformer 40VA 120V to 24V for Model HA1BJX018000ADAA

This OEM replacement transformer (part number HT01AW229) is the factory-specified control circuit transformer for the Carrier HA1BJX018000ADAA. The transformer steps down 120V line voltage to the 24V AC signal required to power the thermostat, control board, and all low-voltage switching components. When the transformer fails, the entire control circuit goes dead — your thermostat will show a blank screen, the system will not respond to any inputs, and no heating or cooling will occur. A failed transformer is often caused by a shorted control wire, a bad contactor coil, or accumulated overload trips.

• Specs: 40VA rating | 120V primary / 24V secondary | Class 2 output | Factory OEM tolerance matched for Carrier control circuits
• OEM vs Generic: The OEM HT01AW229 transformer is wound and rated to exact Carrier specifications. Generic transformers may carry incorrect VA ratings that cause overheating, nuisance tripping, or premature failure of downstream control boards.
• Install Difficulty: 2/5 — Shut off power at the disconnect and breaker before beginning. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, wire nuts or terminal connectors, and a multimeter to verify 24V output after installation. Always photograph existing wiring before disconnecting leads.
• Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Designed as a direct OEM replacement for the Carrier HA1BJX018000ADAA. Always verify your existing transformer's primary voltage, secondary voltage, and VA rating against your unit's data plate before ordering. If you are unsure of fitment, our parts specialists are available to confirm compatibility before you purchase.