OEM Carrier Transformer 40VA 120V/24V for Model HA1AJX018000AAAA

This is the factory OEM replacement transformer (part number HT01AW229) for the Carrier HA1AJX018000AAAA air handler unit. The transformer steps down 120V line voltage to 24V to power the entire low-voltage control circuit — including the thermostat, contactor coil, and control board. When this transformer fails, the result is typically a completely unresponsive system: a blank thermostat display, no contactor pull-in, and no heating or cooling operation. If your system is completely dead with 120V confirmed at the unit but no 24V at the secondary terminals, this transformer is the most likely culprit.

• Specs: 40VA rating | Primary: 120V | Secondary: 24V | OEM part number HT01AW229 | Factory-matched for Carrier HA1AJX018000AAAA air handler
• OEM vs Generic: This factory OEM transformer is wound to exact VA and voltage specifications. Generic replacements often run under-rated VA loads, causing overheating and premature failure — especially when multiple accessories share the 24V circuit.
• Install difficulty: 2/5 — Disconnect power at the breaker before beginning. Tools needed: flathead and Phillips screwdrivers, multimeter, wire nuts or spade connectors. Verify 0V at primary terminals before handling. Photograph all wiring connections prior to removal.
• Warranty: 1-year OEM factory warranty against defects. Orders placed before cutoff ship same business day from our stocked warehouse.

Compatibility: Designed specifically for the Carrier HA1AJX018000AAAA air handler. Verify your unit's control circuit voltage and VA requirements on the data plate before ordering. If you are unsure of fitment, our parts specialists are available to confirm compatibility before you purchase — same-day shipping available on all in-stock OEM parts.