OEM Carrier Control Transformer 40VA 208/240V to 24V for Model PY3GNAA36090NA

This OEM control transformer (part #HT01BD209) is the factory-specified replacement for the Carrier PY3GNAA36090NA. The transformer steps down line voltage (208/240V) to the 24V signal that powers your thermostat, control board, and all low-voltage system components. When it fails, the entire control circuit goes dark — the thermostat becomes unresponsive, the system won't call for heating or cooling, and no fault codes will appear because the board itself has lost power.

• Specs: Input Voltage: 208/240V | Output Voltage: 24V | Power Rating: 40VA | Frequency: 50/60 Hz | Factory OEM part number HT01BD209 | Also replaces legacy part HT01CN232
• OEM vs Generic: OEM transformers are wound to exact VA and voltage tolerances. Undersized or off-tolerance aftermarket transformers can sag under load, causing nuisance lockouts, board resets, and premature contactor wear throughout the control circuit.
• Install difficulty: 2/5 — Shut off all power at the breaker and disconnect switch before servicing. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter. Label all 24V wiring before removing the old transformer. Verify output voltage at 24V terminals before reconnecting the control board.
• Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Designed as the direct OEM replacement for Carrier model PY3GNAA36090NA. Cross-references legacy Carrier part number HT01CN232. Verify input voltage on your unit's data plate (208V or 240V) before ordering — this transformer is rated for both. Need help confirming fitment? Our HVAC parts specialists verify compatibility before you buy.