OEM Carrier 40VA Control Transformer HT01BD209 for Model PY3GNA048090NB

This OEM control transformer is the factory-specified replacement for the Carrier PY3GNA048090NB packaged unit. The transformer steps down 120V line voltage to 24V to power the entire low-voltage control circuit — including the thermostat, contactor coil, and control board. When it fails, the system goes completely unresponsive: no thermostat display, no contactor pull-in, and often a blown 3A or 5A fuse on the control board. Replacing this part with the correct OEM unit restores stable 24V output and protects downstream components from voltage fluctuation.

• Specs: Primary voltage 120V | Secondary voltage 24V | 40VA rating | Factory-matched impedance and thermal cutoff | OEM Part# HT01BD209
• OEM vs Generic: This OEM transformer meets Carrier's exact VA rating and winding tolerances. Undersized or off-brand transformers can sag under load, causing intermittent lockouts, nuisance tripping, or premature control board failure.
• Install Difficulty: 2/5 — Disconnect power at the disconnect box and verify voltage is absent before servicing. Tools needed: flathead and Phillips screwdrivers, wire nuts or spade connectors, multimeter to confirm 24V output after installation. Photograph all wiring before disconnecting.
• Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Designed for the Carrier PY3GNA048090NB packaged unit. Always verify part number HT01BD209 against your unit's wiring diagram or data plate before ordering. Our fitment team is available to confirm compatibility before you buy — no guesswork required. Order now for same-day shipping.