OEM Carrier Control Transformer 120V–24V 40VA for Model PH13NR042000AEAA

This OEM control transformer (part number HT01AW229) is the factory-specified replacement for the Carrier PH13NR042000AEAA heat pump system. Its job is simple but mission-critical: step down 120V line voltage to the 24V AC signal that powers your thermostat, control board, and all low-voltage control circuits. When this transformer fails, the entire control system goes dark — the thermostat goes blank, the unit will not respond to calls for heating or cooling, and no contactors or relays will energize. If you're reading 0V at the R and C terminals on your thermostat, a failed transformer is one of the first components to suspect.

• Specs: Primary voltage: 120V AC | Secondary voltage: 24V AC | VA rating: 40VA | Factory-matched windings and mounting footprint for direct drop-in replacement
• OEM vs Generic: This OEM unit is wound to Carrier's exact VA tolerance, ensuring the control board and thermostat receive a stable, clean 24V signal. Undersized or off-spec generic transformers can cause nuisance lockouts, erratic thermostat behavior, and premature contactor coil burnout.
• Install difficulty: 2/5 — Shut off power at the disconnect and breaker before starting. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter. Verify 0V at primary terminals before touching wiring. Photograph all connections before removal.
• Warranty: 1-year OEM factory warranty against defects. In stock and ships same business day from our warehouse.

Compatibility: Engineered as a direct OEM replacement for the Carrier PH13NR042000AEAA heat pump. Always confirm primary/secondary voltage and VA rating on your unit's data plate before ordering. Our HVAC parts specialists are available to verify fitment — order with confidence.