OEM Carrier Control Transformer 40VA 120V/24V for Model PH3ZPA030000AA

This is the factory-specified OEM control circuit transformer for the Carrier PH3ZPA030000AA packaged heat pump unit. The transformer steps down 120V line voltage to the 24V signal voltage that powers your thermostat, control board, and all low-voltage switching circuits. When this part fails, the entire control circuit goes dead — your thermostat becomes unresponsive, the system won't heat or cool, and no fault codes will display because the board itself has lost power.

• Specs: 40VA output rating | 120V primary / 24V secondary | OEM part number HT01BD242 | Factory-matched for Carrier PH3ZPA030000AA packaged heat pump
• OEM vs Generic: This OEM transformer is wound to exact factory VA and voltage tolerances, protecting sensitive control boards from voltage sag or overvoltage that undersized generic transformers can cause — especially under heavy accessory loads like zone boards or humidifiers.
• Install difficulty: 2/5 — Shut off all power at the disconnect before beginning. Tools needed: flathead and Phillips screwdrivers, multimeter, wire stripper. Photograph or label all low-voltage wiring before disconnecting. Confirm 24V output across secondary terminals with a multimeter before restoring full power.
• Warranty: 1-year OEM factory warranty. Ships same business day from our warehouse when ordered before 3 PM local time.

Compatibility: Designed for the Carrier PH3ZPA030000AA packaged heat pump. Verify transformer VA rating and primary voltage on your unit's data plate before ordering — some configurations may use a different VA rating. Our fitment team is available to confirm compatibility before you buy. Order today for same-day shipping and get your system back online fast.