OEM Carrier Control Transformer 40VA 208/240V to 24V — Model PY2PNB024040AA

This OEM Carrier transformer (part #HT01BD209) is the factory-specified replacement for the Carrier PY2PNB024040AA HVAC system. The control transformer is the heart of your unit's low-voltage circuit — it steps down 208/240V line voltage to the 24V signal voltage that powers your thermostat, contactor coil, control board, and all other low-voltage components. When this transformer fails, the entire control circuit goes dark: your thermostat shows a blank screen, the system stops responding to calls for heating or cooling, and you may measure zero volts at the secondary terminals with a multimeter.

• Specs: 208/240V primary input | 24V secondary output | 40VA power rating | 50/60 Hz | Factory OEM part #HT01BD209 — direct drop-in replacement
• OEM vs Generic: OEM transformers are wound and potted to Carrier's exact tolerances, ensuring clean, stable 24V output. Generic units can run off-voltage, which causes nuisance tripping, erratic board behavior, and premature contactor coil failure.
• Install difficulty: 2/5 — Shut off all power at the disconnect and breaker before beginning. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter (to verify 0V before touching wires and 24V output after installation). Always photograph wiring before disconnecting leads.
• Warranty: 1-year OEM factory warranty. In-stock and ships same business day from our warehouse.

Compatibility: Designed for the Carrier PY2PNB024040AA system. Verify your existing transformer's input voltage, output voltage, and VA rating on the data plate before ordering — mismatched VA ratings can cause overheating or nuisance opens. Not sure if this is the right part? Our HVAC parts specialists verify fitment before you order. Order now and receive same-day shipping!