OEM Carrier Control Transformer 40VA 208/240V to 24V for Model PY3GNAA48115AA

This OEM Carrier control transformer (part number HT01BD209) is the factory-specified replacement for the Carrier PY3GNAA48115AA packaged unit. The transformer steps down the unit's 208/240V line voltage to a safe 24V signal used to power the entire low-voltage control circuit — including the thermostat, control board, and all safety switches. When this transformer fails, the thermostat goes dark, the system refuses to respond to any call for heating or cooling, or you may notice buzzing from the control panel. In short: nothing works until the transformer is replaced.

• Specs: 40VA capacity | 208/240V primary input | 24V secondary output | 50/60 Hz rated | Direct OEM factory replacement
• OEM vs Generic: This is a genuine Carrier OEM part — wound and insulated to exact factory tolerances. Aftermarket transformers can run outside rated VA, leading to nuisance tripping of downstream fuses and premature control board failure. Choose OEM to protect the entire control circuit.
• Install difficulty: 2/5 — Shut off all power and verify zero voltage before touching any wiring. Tools needed: flathead and Phillips screwdrivers, multimeter, wire labels or tape. Always photograph all low-voltage wiring before disconnecting. Check and replace any blown 3A control fuse in the same service call.
• Warranty: 1-year OEM manufacturer warranty. In stock and ships same business day from our warehouse.

Compatibility: Factory-matched for Carrier model PY3GNAA48115AA. Also supersedes/replaces OEM part numbers HT01BD207, HT01CN232, and 9076-00. Confirm input voltage on your unit's data plate (208V or 240V) before ordering — this transformer is rated for both. Questions about fitment? Our HVAC parts specialists verify compatibility before you buy. Order now and get same-day shipping on all in-stock parts.