OEM Carrier 40VA Control Transformer HT01BD209 for Model PY3PNA024040NB

This OEM control transformer (part number HT01BD209) is the factory-specified replacement for the Carrier PY3PNA024040NB packaged unit. The transformer steps down 120V line voltage to the 24V AC signal that powers your thermostat, control board, and all low-voltage switching circuits. When this part fails, the entire control circuit goes dark — the thermostat loses power, the system becomes completely unresponsive, and no heating or cooling function can be initiated.

• Specs: 40VA rating | 120V primary / 24V secondary | Factory OEM tolerance | Matches original footprint and wire terminals for direct drop-in replacement
• OEM vs Generic: This is a genuine Carrier OEM transformer built to exact VA and voltage specifications. Generic alternatives may carry insufficient VA capacity, causing thermal overload trips under normal control-circuit loads and premature failure.
• Install difficulty: 2/5 — Disconnect all power before beginning. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter (to verify 24V output after install). Always label or photograph wire connections before removing the old unit.
• Warranty: 1-year OEM factory warranty. In-stock units ship same business day from our warehouse.

Compatibility: Designed for the Carrier PY3PNA024040NB packaged unit. Verify transformer VA rating and primary/secondary voltages on your unit's data plate before ordering. Not sure it fits? Our technical team confirms fitment before you buy — reach out before placing your order.