OEM Carrier Control Transformer 40VA 208/240V to 24V for Model PY4GPAA60090AA

This genuine OEM Carrier control transformer (part #HT01BD209) is the factory-specified replacement for the Carrier PY4GPAA60090AA packaged unit. The transformer steps down high-voltage line power (208/240V) to the 24V signal required by your thermostat, control board, and all low-voltage components. When this part fails, the entire control circuit goes dead — the thermostat loses power, contactors won't energize, and the system will not respond to any call for heating or cooling. If your unit is completely unresponsive and your high-voltage power supply checks out, this transformer is the first component to test.

• Specs: 208/240V Primary | 24V Secondary | 40VA Rating | 50/60 Hz | Factory OEM part #HT01BD209
• OEM vs Generic: OEM transformers are wound and insulated to exact factory VA and voltage tolerances, protecting sensitive control boards from voltage fluctuations. Generic units may run slightly over or under 24V, risking premature board failure.
• Install Difficulty: 2/5 — Shut off all power at the breaker and disconnect switch before servicing. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, wire stripper, multimeter. Label or photograph all low-voltage wiring before removal. Double-check polarity on secondary leads.
• Warranty: 1-year OEM factory warranty. Ships same business day from our warehouse — get your system back online fast.

Compatibility: Factory-matched for Carrier model PY4GPAA60090AA. This part also replaces superseded Carrier part numbers HT01BD207, HT01CN232, and 9076-00. Always verify your unit's data plate voltage before ordering. Our fitment team is available to confirm compatibility before you buy.