OEM Carrier Control Transformer 40VA 208/230–24V for Model PY3GNA030040NA

This is the genuine OEM Carrier control transformer (part #HT01BD209) factory-specified for the Carrier PY3GNA030040NA packaged unit. The transformer steps high-voltage line power (208/230V) down to the 24V signal that energizes your thermostat, control board, contactor coil, and every other low-voltage circuit in the system. When it fails, the entire control circuit goes dark — nothing calls for heat or cooling, the thermostat appears dead, and the unit may enter a no-response lockout condition. If your system is completely unresponsive but line voltage at the unit checks out, a failed transformer is the first component to test.

• Specs: 40VA capacity | 208/230V primary input | 24V secondary output | 50/60 Hz | OEM part #HT01BD209 | Also replaces HT01BD207 & HT01CN232
• OEM vs Generic: This is a genuine Carrier OEM transformer wound to exact VA and voltage tolerances. Generic aftermarket units often run at looser tolerances, risking nuisance tripping of the onboard fuse or undervoltage faults at the control board — particularly under high-demand starts.
• Install difficulty: 2/5 — Shut off all power at the disconnect before touching any wiring. Tools needed: flathead and Phillips screwdrivers, multimeter (to confirm 0V before and 24V after). Photograph all low-voltage wiring connections prior to removal. Typically a 15–30 minute replacement for an experienced technician.
• Warranty & Shipping: 1-year OEM factory warranty against defects. In stock and ships same business day from our warehouse. Free ground shipping on qualifying orders.

Compatibility: Factory-matched replacement for Carrier PY3GNA030040NA packaged units. Cross-references OEM part numbers HT01BD207 and HT01CN232. Always verify your unit's data plate voltage (208/230V primary) before ordering. Our fitment team is available to confirm compatibility before you buy — just reach out before placing your order.