OEM Carrier Transformer 40VA 120V/24V for Model PY3PPA048090NA

This OEM replacement transformer (part number HT01BD209) is the factory-specified control circuit transformer for the Carrier PY3PPA048090NA packaged unit. The transformer steps down 120V line voltage to the 24V signal voltage that powers your thermostat, control board, contactors, and safety switches. When it fails, absolutely nothing responds — the thermostat goes blank, the system won't call for heat or cooling, and no components energize. Replacing it with the correct OEM unit restores the entire low-voltage control circuit instantly.

• Specs: 120V primary | 24V secondary output | 40VA rating | Factory-matched to Carrier PY3PPA048090NA low-voltage circuit requirements
• OEM vs Generic: OEM transformers are wound and rated to exact factory VA specifications, ensuring stable 24V output under full control-circuit load. Generic units often run undervoltage at peak demand, causing nuisance lockouts, contactor chatter, and premature board failure.
• Install difficulty: 2/5 — Turn off power at the disconnect and breaker before beginning. Tools needed: flathead and Phillips screwdrivers, wire nuts or spade terminals, multimeter to verify 24V output after installation. Photograph all wiring connections before removing the old unit.
• Warranty: 1-year OEM factory warranty. In-stock and ships same business day from our warehouse.

Compatibility: Designed for the Carrier PY3PPA048090NA packaged unit. Always verify your unit's control-circuit voltage and VA requirements on the data plate before ordering. If you need help confirming fitment, our HVAC parts specialists are available to verify before you buy — contact us before placing your order.