OEM Carrier Control Transformer 40VA 120V–24V for Model PH13NB042000AAAA

This OEM Carrier transformer (part number HT01AW229) is the factory-specified replacement for the Carrier PH13NB042000AAAA heat pump system. The transformer steps down line voltage (120V) to low-voltage control circuit power (24V AC), energizing the thermostat, contactor coil, and all control board logic. When it fails, the entire control circuit goes dead — the thermostat displays nothing, the system won't respond to any call for heating or cooling, and you may find a blown 3A fuse on the control board as a secondary symptom.

• Specs: 40VA rating | Primary: 120V AC | Secondary: 24V AC | Factory-matched OEM construction | Replaces OEM part number HT01AW229
• OEM vs Generic: This OEM unit meets Carrier's exact VA rating and insulation class. Undersized or off-tolerance generic transformers can overheat, trip thermal cutoffs prematurely, or fail to hold 24V under load — causing intermittent lockouts that are difficult to diagnose.
• Install difficulty: 2/5 — Disconnect power at the breaker and verify zero voltage with a multimeter before touching any wiring. Tools needed: flathead and Phillips screwdrivers, multimeter, wire nuts or spade connectors. Photograph all wiring before disconnecting. Replace the 3A control fuse if blown during the same service call.
• Warranty: 1-year OEM factory warranty against defects. In-stock and ships same business day from our warehouse.

Compatibility: Designed as a direct OEM replacement for the Carrier PH13NB042000AAAA heat pump. Verify primary voltage (120V) and secondary voltage (24V) against your unit's data plate before ordering. Our team is available to confirm fitment — reach out before you buy if you have any questions.