OEM Carrier Control Transformer 40VA 208/230V to 24V for Model PY3GNAA42060AA

This genuine OEM Carrier control transformer (part #HT01BD209) is the factory-specified replacement for the Carrier PY3GNAA42060AA packaged unit. The transformer steps down 208/230V line voltage to the 24V AC signal that powers your thermostat, control board, contactor coil, and every other low-voltage component in the system. When the transformer fails—due to a shorted control wire, a failed component drawing excess current, or simple age—nothing in the system responds: the thermostat goes blank, the unit refuses to start, and breakers may trip repeatedly. Replacing the transformer is the first diagnostic step when the entire control circuit goes dark.

• Specs: 208/230V primary | 24V secondary | 40VA rated | 50/60 Hz | Replaces OEM part numbers HT01BD207, HT01CN232, and 9076-00
• OEM vs Generic: OEM transformers are wound and potted to exact Carrier VA and impedance specifications, protecting downstream control boards from voltage spikes. Generic units often run unregulated secondary voltage that can damage sensitive electronics over time.
• Install difficulty: 2/5 — De-energize the unit at the disconnect and verify zero voltage with a multimeter before touching any terminals. Photograph all wiring before disconnecting. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter. Always inspect low-voltage wiring for shorts before powering up the new transformer.
• Warranty: 1-year OEM factory warranty. Ships same business day from our warehouse.

Compatibility: Factory-matched for the Carrier PY3GNAA42060AA packaged unit. Verify your unit's data plate primary voltage (208V or 230V) before ordering — this transformer supports both. Questions about fitment? Our team confirms compatibility before you order.