OEM Carrier Control Transformer 40VA 208/240V to 24V for Model PY4GPAA48090AA

This is the genuine OEM control transformer (part #HT01BD209) factory-specified for the Carrier PY4GPAA48090AA packaged HVAC unit. The transformer steps down 208/240V line voltage to the 24V signal used by your thermostat, control board, gas valve, and every other low-voltage component in the system. When it fails, the result is total loss of control circuit power — nothing responds, the thermostat goes blank, and the unit will not start. A failed transformer is often misdiagnosed as a bad board, making correct identification critical before replacing more expensive components.

• Specs: 40VA capacity | 208/240V primary input | 24V secondary output | 50/60Hz | OEM part number HT01BD209 | Also cross-references HT01BD207, HT01CN232, and 9076-00
• OEM vs Generic: OEM transformers are wound to exact factory VA tolerances, protecting sensitive control boards from voltage fluctuation. Generic units often run under-spec VA ratings, causing nuisance trips and premature board failure under full system load.
• Install difficulty: 2/5 — Shut off all power at the breaker before beginning. Tools needed: flathead and Phillips screwdrivers, multimeter, wire stripper. Always verify 24V output with a meter before reconnecting controls. Photograph existing wiring before disconnecting.
• Warranty: 1-year OEM factory warranty against defects. Ships same business day from our warehouse.

Compatibility: Factory-matched for Carrier model PY4GPAA48090AA packaged HVAC unit. Also compatible with select Bryant and Payne models using the same 40VA, 208/240V-to-24V transformer specification — verify your unit's data plate and wiring diagram before ordering. Have questions? Our fitment team confirms compatibility before you buy.