OEM Carrier Control Transformer 40VA 208/230V → 24V for Model PY4GPAA60130AA

This genuine OEM Carrier control transformer (part #HT01BD209) is the factory-specified replacement for the Carrier PY4GPAA60130AA packaged unit. The transformer steps down line voltage from 208/230V to 24V to power the low-voltage control circuit — including the thermostat, contactor coil, gas valve, and control board. When this transformer fails, the entire control circuit goes dead: the thermostat goes blank, nothing responds to a call for heat or cooling, and the system will not start at all. If you're reading 0V on the secondary (R and C terminals) at the air handler, this transformer is the first component to test and replace.

• Specs: 40VA capacity | 208/230V primary input | 24V secondary output | 50/60 Hz | Factory cross-reference: replaces HT01BD207, HT01CN232, and 9076-00
• OEM vs Generic: The OEM HT01BD209 is wound and potted to exact Carrier factory tolerances, ensuring a stable 24V output under full load. Generic transformers can sag under load, causing erratic thermostat behavior and intermittent lockouts that are difficult to diagnose.
• Install difficulty: 2/5 — Shut off all power (line and low-voltage) before beginning. Tools needed: flathead and Phillips screwdrivers, multimeter, needle-nose pliers. Label all 24V wire connections before disconnecting. Torque wire-nut connections firmly — loose low-voltage wiring is a common callback cause.
• Warranty: 1-year OEM factory warranty. Ships same business day from our warehouse in original factory packaging.

Compatibility: Direct OEM replacement for Carrier PY4GPAA60130AA packaged units. Verify your unit's model and serial number on the data plate before ordering — primary input voltage (208V vs 230V) must match your supply circuit. Questions about fitment? Our HVAC parts team confirms compatibility before you buy. Order before 3PM and your part ships today.