OEM Carrier 40VA Control Transformer for Model HA1BJX036000ABAA

This OEM replacement transformer (part number HT01AW229) is the factory-specified control circuit transformer for the Carrier HA1BJX036000ABAA unit. Its primary function is to step down 120V line voltage to the 24V signal voltage required to power your thermostat, control board, contactor coil, and all low-voltage safety circuits. When this transformer fails, the entire control circuit goes dead — your thermostat goes blank, your system will not respond to any call for heating or cooling, and in many cases a tripped secondary fuse is the first clue. Replacing the transformer is often the fastest and most affordable fix before condemning an expensive control board.

• Specs: Primary voltage: 120V AC | Secondary voltage: 24V AC | VA rating: 40VA | OEM part number: HT01AW229 | Factory-matched construction for Carrier low-voltage control circuits
• OEM vs Generic: This is the factory OEM transformer, wound to exact VA and impedance specifications. Generic transformers frequently have inconsistent VA output that can underpower contactor coils and cause nuisance lockouts or premature control board failure.
• Install difficulty: 2/5 — Disconnect all power before servicing. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter for voltage verification post-install. Note wire colors and terminal positions before removing the old transformer. Confirm 24V output at secondary terminals before restoring full system power.
• Warranty: 1-year OEM factory warranty. In-stock and ships same business day from our NationalHVACParts.com warehouse.

Compatibility: Engineered specifically for the Carrier HA1BJX036000ABAA unit. Always verify your existing transformer's VA rating and primary/secondary voltages on the data plate or wiring diagram before ordering. If you have any fitment questions, our parts specialists are available to confirm compatibility before you purchase — ensuring the right part arrives the first time.