OEM Carrier Control Transformer 40VA 208/240V to 24V for Model PY3GNAA48115NA

This OEM control transformer (part number HT01BD209) is the factory-specified replacement for the Carrier PY3GNAA48115NA packaged unit. The transformer steps down the 208/240V line voltage to the 24V signal voltage that powers your thermostat, control board, contactor coil, and all other low-voltage control circuit components. When this transformer fails, the entire control circuit goes dark — your thermostat becomes unresponsive, the system won't cycle on, and no error codes will appear because the board itself has lost power.

• Specs: 208/240V Primary | 24V Secondary | 40VA Rating | 50/60Hz | Class 2 Control Transformer — factory-matched to Carrier OEM spec
• OEM vs Generic: Genuine Carrier OEM transformers are wound to exact VA and voltage tolerances. Undersized or out-of-spec generic units can brown out control boards and shorten contactor coil life — always match the original VA rating.
• Install Difficulty: 2/5 — Always switch off line voltage at the disconnect and confirm zero voltage with a multimeter before touching any wiring. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter. Photograph all low-voltage and line-voltage wiring connections before disconnecting. Reconnect secondary (24V) wires first, then primary (line voltage) wires.
• Warranty: 1-year OEM factory warranty against defects. Ships same business day from our warehouse. Also replaces legacy part numbers HT01BD207 and HT01CN232.

Compatibility: Direct OEM replacement for Carrier model PY3GNAA48115NA packaged units. Verify your existing transformer's primary voltage (208/240V), secondary voltage (24V), and VA rating (40VA) against your unit data plate before ordering. Not sure it fits? Our HVAC parts team confirms fitment before you buy — order with confidence and get it shipped today.