OEM Carrier Transformer 40VA 120V–24V for Model HA1BJX024000ACAA

This OEM step-down transformer (part# HT01AW229) is the factory-specified replacement for the Carrier HA1BJX024000ACAA air handler. The transformer converts 120V line voltage down to the 24V AC signal that powers the entire control circuit — including the thermostat, control board, contactor coil, and zone controls. When this component fails, nothing in the system responds: the thermostat goes blank, the blower won't start, and no error codes are generated because the control board itself has no power. If you've confirmed 120V supply to the unit but zero 24V output on your secondary terminals, this transformer is almost certainly the culprit.

• Specs: 40VA rating | Primary: 120V AC | Secondary: 24V AC | OEM part number HT01AW229 | Factory-matched output tolerance for stable low-voltage circuit performance
• OEM vs Generic: OEM transformers are wound and rated to exact factory specifications, ensuring the secondary voltage stays within the tight tolerance required by modern control boards. Undersized or off-spec generic transformers can cause nuisance tripping of the 3A control fuse or premature board failure.
• Install difficulty: 2/5 — Disconnect all power before servicing. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter. Identify and label all 24V secondary wiring before disconnecting. Verify 120V primary input before condemning the transformer.
• Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Designed specifically for the Carrier HA1BJX024000ACAA air handler. Always verify your existing transformer's VA rating and primary/secondary voltages on the unit data plate or wiring diagram before ordering. Our fitment team is available to confirm compatibility before you buy — order with confidence and get back to comfort fast.