OEM Carrier Control Transformer 40VA 208/240V to 24V — HT01BD209 for Model PY2PNB030040AB

The Carrier HT01BD209 is the factory OEM control transformer for the Carrier PY2PNB030040AB packaged unit. Its sole job is to step down high-voltage line power (208/240V) to the 24V AC signal that drives every low-voltage component in your system — the thermostat, control board, contactor coil, and zone controls. When this transformer fails, the entire low-voltage control circuit goes dark: your thermostat goes blank, the system will not respond to any call for heating or cooling, and no fault codes appear because the board itself has no power. A failed transformer is often misdiagnosed as a control board failure, making correct identification critical before replacing more expensive components.

• Specs: 40VA capacity | 208/240V primary input | 24V secondary output | 50/60 Hz rated | Replaces OEM part numbers HT01BD207, HT01CN232, and 9076-00
• OEM vs Generic: This is a genuine Carrier OEM transformer wound to exact factory VA and voltage tolerances. Generic transformers frequently run under-spec VA ratings, causing premature burnout — especially on systems with multiple 24V zone valves or damper actuators on the same circuit.
• Install difficulty: 2/5 — Turn off all power to the unit at the disconnect and breaker before touching any wiring. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter. Always confirm 0V at the primary terminals before handling. Label all wire connections before removal.
• Warranty: 1-year OEM factory warranty. In-stock and ships same business day from our warehouse.

Compatibility: Direct factory replacement for Carrier model PY2PNB030040AB packaged units. Cross-references: HT01BD207, HT01CN232, 9076-00, 4000A46E07AE28. Verify your existing transformer's primary voltage (208/240V) and VA rating (40VA) on the data plate before ordering. Have questions about fitment? Our HVAC parts specialists verify compatibility before you order — contact us today and get your unit back online fast.