OEM Carrier Control Transformer 40VA 208/240V to 24V for Model SUBCLR50HJ402500

This OEM Carrier control transformer (part number HT01BD209) is the factory-specified replacement for the SUBCLR50HJ402500 HVAC system. The transformer steps down high-voltage line power (208/240V) to the 24V signal needed to energize your thermostat, control board, contactor coil, and all low-voltage system logic. When this part fails, the entire control circuit goes dead — the thermostat loses power, nothing calls for heating or cooling, and the system will not respond to any input. A failed transformer is often misdiagnosed as a board failure, making correct identification critical before replacing more expensive components.

• Specs: 40VA capacity | Primary voltage: 208/240V | Secondary voltage: 24V | Frequency: 50/60 Hz | OEM part number HT01BD209 | Also replaces HT01BD207, HT01CN232, 9076-00
• OEM vs Generic: This genuine Carrier OEM transformer is wound and rated to exact factory specifications. Aftermarket units often underrate their VA capacity, causing overheating and nuisance tripping of the internal fuse — a common callback source for techs who use non-OEM replacements.
• Install difficulty: 2/5 — Shut off all power to the unit before servicing. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter. Label or photograph all low-voltage wiring terminals before disconnecting. Improper wiring polarity can damage the new transformer or downstream controls.
• Warranty: 1-year OEM factory warranty. Ships same business day from our warehouse — order by 3PM local time for guaranteed same-day dispatch.

Compatibility: Designed for Carrier model SUBCLR50HJ402500. Verify primary voltage (208V or 240V) and VA rating on your unit's data plate before ordering. If you are unsure whether this part fits your exact serial number variant, contact our parts team — we verify fitment before you buy.