OEM Carrier 40VA Control Transformer for Model HB1AJX036000AAAA

This OEM replacement transformer (part number HT01AW229) is the factory-specified control circuit transformer for the Carrier HB1AJX036000AAAA air handler. The transformer steps line voltage (120V) down to 24V AC to power the low-voltage control circuit — including the thermostat, contactor coil, and control board. When it fails, nothing in the system responds: the thermostat goes blank, the unit won't call for heating or cooling, and the entire low-voltage circuit goes dead. A failed transformer is one of the most commonly misdiagnosed faults in HVAC service calls.

• Specs: 40VA rating | 120V primary / 24V secondary | Class 2 transformer | Direct OEM replacement for part number HT01AW229
• OEM vs Generic: OEM transformers are wound to exact VA and voltage tolerances required by Carrier's control board. Undersized or off-tolerance generic units can overheat, trip internal thermal protectors, or cause erratic low-voltage behavior that mimics other faults.
• Install difficulty: 2/5 — Shut off all power before beginning. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter. Verify 0V at primary terminals before disconnecting wiring. Photograph or label all wires prior to removal.
• Warranty: 1-year OEM factory warranty. In-stock and ships same business day from our warehouse.

Compatibility: Engineered as a direct OEM fit for the Carrier HB1AJX036000AAAA air handler. Always confirm the primary voltage and VA rating on your existing transformer's label before ordering to ensure proper match. Have questions about fitment? Our HVAC parts specialists verify compatibility before you buy — same-day shipping available on all in-stock orders.