OEM Carrier Control Transformer 40VA 208/240V to 24V for Model PY4GNAA24060AA

This OEM Carrier transformer (part #HT01BD209) is the factory-specified replacement for the Carrier PY4GNAA24060AA packaged unit. The control transformer steps down high-voltage supply power (208/240V) to the 24V DC signal required by the thermostat, control board, contactors, and all low-voltage safety circuits. When this part fails, the entire control circuit goes dead — the thermostat goes blank, the system will not respond to any call for heating or cooling, and no fault codes will display because the board itself has no power. This is often misdiagnosed as a thermostat or control board failure, making correct identification of the transformer critical before replacing more expensive components.

• Specs: 208/240V primary input | 24V secondary output | 40VA power rating | 50/60Hz dual frequency | OEM part #HT01BD209 | Factory direct fit
• OEM vs Generic: OEM transformers are wound to exact factory VA and voltage tolerances, ensuring the 24V output stays stable under full control circuit load. Generic units often under-deliver under load, causing nuisance lockouts and intermittent control issues that are difficult to diagnose.
• Install difficulty: 2/5 — Shut off all power at the disconnect and breaker before beginning. Tools needed: flathead and Phillips screwdrivers, multimeter, needle-nose pliers. Photograph all low-voltage wiring connections before disconnecting. Verify 24V output with a multimeter after installation before restoring system power.
• Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Direct OEM replacement for Carrier PY4GNAA24060AA packaged units. Always verify your unit's data plate voltage rating matches the 208/240V primary specification before ordering. Not sure if this is the right part? Our HVAC parts specialists verify fitment before you order — reach out before you buy.