OEM Carrier Control Transformer 40VA 208/240V to 24V for Model PY3GNAA30040NA

This OEM control transformer (part number HT01BD209) is the factory-specified replacement for the Carrier PY3GNAA30040NA system. The transformer steps down line voltage from 208/240V to the 24V signal required by your thermostat, control board, contactor coil, and all low-voltage safety circuits. When this component fails, the entire 24V control circuit goes dark — the thermostat becomes unresponsive, the system will not energize, and no call for heating or cooling is answered. It is one of the first components an experienced technician checks when a unit shows zero response to any thermostat command.

• Specs: 40VA capacity | 208/240V primary input | 24V secondary output | 50/60 Hz | Class 2 control transformer | Factory-matched Carrier OEM specification
• OEM vs Generic: This is a genuine Carrier OEM part built to exact factory tolerances. Generic transformers may carry higher VA ripple and looser voltage output tolerances, which can stress sensitive control boards and solid-state components over time. OEM is the only safe choice for critical 24V control circuits.
• Install difficulty: 2/5 — Shut off all power at the disconnect and breaker before touching any wiring. Tools needed: flat-head and Phillips screwdrivers, wire stripper, multimeter. Label or photograph all low-voltage wiring before disconnecting. Confirm output voltage with a multimeter after installation before restoring full power.
• Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Designed for the Carrier PY3GNAA30040NA. Also replaces legacy part numbers HT01BD207, HT01CN232, and 9076-00. Always verify your unit's data plate voltage specifications match the 208/240V primary rating before ordering. Our team is available to confirm fitment — just reach out before you buy. Order today and receive same-day shipping on all in-stock parts.