OEM Carrier Control Transformer 40VA 208/230V to 24V — HT01BD209 for Model PY3PNA036090NB

The Carrier HT01BD209 is the factory-specified OEM control transformer for the PY3PNA036090NB packaged unit. This transformer steps down 208/230V line voltage to the 24V signal voltage that powers your thermostat, control board, and all low-voltage safety circuits. When it fails, the result is immediate and total: the thermostat goes dark, no call for heat or cooling is processed, and the system is completely unresponsive — often misdiagnosed as a control board failure.

• Specs: 208/230V primary | 24V secondary | 40VA rating | 50/60 Hz | Class 2 control transformer | OEM part number HT01BD209 (replaces HT01BD207, HT01CN232, 9076-00)
• OEM vs Generic: The OEM Carrier transformer is wound to exact VA and voltage tolerances required by the PY3PNA036090NB control circuit. Undersized or off-tolerance generic transformers can cause nuisance lockouts, brownout trips on the secondary side, and premature control board failure.
• Install difficulty: 2/5 — Always disconnect power and verify zero voltage at the unit before beginning. Tools needed: multimeter, flathead and Phillips screwdrivers, wire nuts or spade terminals. Label all low-voltage wires before disconnecting. Confirm 24V output with a multimeter after installation before restoring full power.
• Warranty: 1-year OEM factory warranty. In-stock and ships same business day from our warehouse.

Compatibility: Designed for the Carrier PY3PNA036090NB packaged unit. Also cross-references to Bryant and Payne models using the same control transformer specification. Verify your existing transformer's VA rating and primary voltage on the unit data plate before ordering. Need help confirming fitment? Our HVAC parts specialists verify compatibility before you buy — no guesswork.