OEM Payne 40VA Control Transformer for Model PA3ZPA048000AA

This OEM replacement transformer (part# HT01BD242) is the factory-specified control circuit transformer for the Payne PA3ZPA048000AA packaged air conditioner. The transformer steps down line voltage (120V) to the 24V signal voltage required to power the thermostat, control board, contactor coil, and all low-voltage safety controls. When this component fails, the entire control circuit goes dark — the thermostat loses power, the system becomes completely unresponsive, and no heating or cooling function is possible. A failed transformer is often misdiagnosed as a thermostat or control board failure, making it a critical first check.

• Specs: 40VA rating | Primary: 120V | Secondary: 24V | Factory-matched OEM tolerance | Part Number: HT01BD242
• OEM vs Generic: This is the genuine OEM Payne transformer, wound and rated to exact factory specifications. Generic alternatives often carry lower VA ratings or looser voltage tolerances, risking nuisance tripping on 24V fuses or premature control board failure.
• Install difficulty: 2/5 — Shut off all power at the disconnect and breaker before starting. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter (to verify 24V output after install). Photograph existing wire connections before disconnecting the primary and secondary leads.
• Warranty: 1-year OEM factory warranty against defects. In-stock and ships same business day from our warehouse.

Compatibility: Designed specifically for the Payne PA3ZPA048000AA packaged air conditioner (4-ton, R-410A). Always verify your unit's data plate voltage requirements match before ordering. If your system repeatedly blows the 24V fuse, inspect for shorted wiring before installing the new transformer. Our fitment team is available to confirm compatibility before you order — reach out before you buy.