OEM Carrier Control Transformer 40VA 208/240V to 24V for Model PY3PNA042090AA

This is the genuine OEM control transformer (part number HT01BD209) factory-specified for the Carrier PY3PNA042090AA. The transformer steps down 208/240V line voltage to a stable 24V signal that powers your thermostat, control board, gas valve, and all low-voltage safety circuits. When this transformer fails, the entire control circuit goes dark — the thermostat becomes unresponsive, the system won't call for heating or cooling, and no safety safeties can operate. A failed transformer is one of the most common reasons a system appears completely dead despite having power at the disconnect.

• Specs: 208/240V Primary | 24V Secondary | 40VA rated | 50/60Hz | Class 2 control transformer | Direct OEM replacement for HT01BD207, HT01CN232, and 9076-00
• OEM vs Generic: This OEM unit is wound to exact Carrier factory tolerances, ensuring steady 24V output under full VA load. Generic transformers can sag under load, causing nuisance lockouts, erratic thermostat behavior, or premature control board failure.
• Install difficulty: 2/5 — Shut off all power at the disconnect and breaker before beginning. Tools needed: flathead and Phillips screwdrivers, wire strippers, multimeter. Label all low-voltage wiring before disconnecting. Confirm 24V output with a multimeter after installation before restoring system operation.
• Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Engineered as the factory-matched replacement for Carrier model PY3PNA042090AA. Also replaces obsolete Carrier part numbers HT01BD207, HT01CN232, and 9076-00. Verify your unit's model and serial number before ordering, or contact our team for fitment confirmation before you buy.