OEM Carrier 40VA Control Transformer 120V–24V for Model PY3PPA036060NA

This is the factory OEM replacement control transformer (part #HT01BD209) for the Carrier PY3PPA036060NA packaged unit. The transformer steps down 120V line voltage to the 24V AC signal that powers your thermostat, control board, and all low-voltage switching circuits. When it fails, the entire control circuit goes dead — the thermostat goes blank, the system won't respond to any call for heating or cooling, and nothing powers up. It is one of the most commonly overlooked failure points during a no-call diagnostic.

• Specs: Input: 120V AC | Output: 24V AC | Rating: 40VA | Factory-matched OEM wiring and mounting configuration for direct drop-in replacement
• OEM vs Generic: The OEM HT01BD209 transformer meets Carrier's exact VA rating and insulation class. Generic units may run undersized VA tolerances, causing thermal overload and premature control board failure — especially under high demand from multiple zone valves or accessory loads.
• Install Difficulty: 2/5 — Shut off all power to the unit before servicing. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter. Label and photograph all low-voltage wiring before disconnecting. Confirm primary voltage at the unit before installing.
• Warranty: 1-year OEM factory warranty. In-stock and ships same business day from our warehouse.

Compatibility: Engineered as a direct OEM fit for Carrier model PY3PPA036060NA. Always verify your unit's control voltage and VA requirement on the data plate or wiring diagram before ordering. Our fitment team is available to confirm compatibility before you buy — order with confidence from NationalHVACParts.com.