OEM Carrier Control Transformer 40VA for Model PY3GNAA48090AA

This is the OEM factory-specified replacement transformer (part # HT01BD209) for the Carrier PY3GNAA48090AA packaged unit. The transformer steps down line voltage (120V or 240V) to the 24V AC signal that powers the entire control circuit — including the thermostat, contactor coil, reversing valve, and control board. When this transformer fails, the system goes completely silent: no thermostat response, no staging, no fan — nothing works. It is often the first component to diagnose when a system shows zero 24V output at the control board.

• Specs: 40VA rating | Primary: 120/240V | Secondary: 24V AC | OEM part number HT01BD209 | Factory-matched windings and mounting footprint
• OEM vs Generic: This is the exact OEM unit built to Carrier's factory tolerances. Generic transformers may carry a wider VA variance, leading to undervoltage on the control circuit, nuisance lockouts, and premature contactor coil failure.
• Install Difficulty: 2/5 — Shut off all power at the disconnect and verify zero voltage with a multimeter before touching any wiring. Tools needed: flathead and Phillips screwdrivers, multimeter, wire nuts or spade connectors. Photograph all wiring connections before removal.
• Warranty: 1-year OEM factory warranty. In-stock and ships the same business day from our warehouse.

Compatibility: Designed for the Carrier PY3GNAA48090AA packaged unit. Always verify your unit's data plate voltage and VA requirements before ordering. Not sure it fits? Our HVAC parts specialists confirm fitment before you buy — contact us today and get your system back online fast.