OEM Carrier 40VA Control Transformer for Model PH12NA04200GABAA

This is the factory OEM replacement control transformer (part number HT01AW229) for the Carrier PH12NA04200GABAA heat pump system. The transformer steps down line voltage from 120V to 24V to power the low-voltage control circuit — including the thermostat, contactor coil, and control board. When it fails, the entire control circuit goes dead: the thermostat goes blank, the system won't respond to any calls for heating or cooling, and there is no 24V signal present at the board.

• Specs: 120V primary | 24V secondary | 40VA rating | Factory OEM part number HT01AW229 | Direct plug-and-play replacement with OEM wiring connectors
• OEM vs Generic: This is the exact factory-specified transformer. OEM units are wound to precise VA ratings and insulation standards. Generic transformers often run undersized VA ratings that can cause voltage sag under load, nuisance tripping, and premature control board failure.
• Install difficulty: 2/5 — Disconnect power at the breaker and verify with a multimeter before touching any wiring. Tools needed: flathead and Phillips screwdrivers, multimeter, wire nuts or spade connectors. Photograph all wiring before removal. Test output voltage after installation before closing the cabinet.
• Warranty: 1-year OEM factory warranty against defects in materials and workmanship. In-stock and ships same business day from our NationalHVACParts.com warehouse.

Compatibility: Designed and tested for the Carrier PH12NA04200GABAA heat pump. Always verify your existing transformer's VA rating and primary/secondary voltages against your unit's data plate before ordering. Not sure it fits? Our HVAC parts specialists confirm fitment before you buy — no guesswork, no returns.