OEM Carrier Control Transformer 40VA 208/240V to 24V — HT01BD209 for Model PY3GNAA60090AA

The Carrier HT01BD209 control transformer is the factory-specified OEM replacement for the Carrier PY3GNAA60090AA packaged HVAC system. This transformer steps high-voltage line power (208/240V) down to the 24V signal used by your thermostat, control board, contactor coil, and all other low-voltage components. When it fails, nothing in the control circuit responds — the system will appear completely dead even with line voltage present at the unit. A blown fuse on the secondary side is the most common symptom, often caused by a short in the low-voltage wiring.

• Specs: 40VA output | 208/240V primary | 24V secondary | 50/60Hz | OEM part number HT01BD209 | Replaces HT01BD207, HT01CN232, and 9076-00
• OEM vs Generic: This is a genuine Carrier OEM transformer wound to exact factory VA and voltage tolerances. Generic transformers frequently underperform at rated VA load, causing nuisance low-voltage faults, premature contactor coil burnout, and control board instability.
• Install difficulty: 2/5 — Disconnect all power before servicing. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter. Label all low-voltage wires before disconnecting. Always check for a short in the low-voltage circuit before powering up the replacement to avoid blowing the secondary fuse again.
• Warranty: 1-year OEM factory warranty. Orders placed before 3PM ship same business day from our warehouse.

Compatibility: Engineered as a direct OEM fit for Carrier model PY3GNAA60090AA. Verify your unit's data plate shows 208/240V primary input and a 40VA, 24V secondary before ordering. Bryant and Payne units sharing this transformer platform are also covered. Our fitment team is available to confirm compatibility before you buy — no guesswork.