OEM Carrier Furnace Transformer 120V to 24V 40VA — HT01CN001 for Model UPFLOW250U12020AL

This is the factory-specified OEM replacement transformer for the Carrier UPFLOW250U12020AL upflow gas furnace. The transformer steps down 120V line voltage to a safe 24V (with 12V tap) for the furnace's control circuit — powering the thermostat, control board, gas valve relay, and all low-voltage safety circuits. When it fails, the entire control circuit goes dark: the thermostat shows no power, the system refuses to respond to any call for heat or cooling, and you may notice a faint buzzing or burning smell near the transformer itself.

• Specs: 120V primary | 12V / 24V secondary | 40VA rated | Factory-authorized OEM part | Replaces legacy part numbers HT01BJ115, 19EA41612, and 19EA42612
• OEM vs Generic: The OEM HT01CN001 is wound to Carrier's exact VA rating and insulation class, ensuring the control board and gas valve receive stable, clean 24V power. Generic transformers with loose VA tolerances can cause nuisance lockouts, erratic thermostat behavior, or premature control board failure.
• Install difficulty: 3/5 — Shut off power at the breaker and verify zero voltage with a multimeter before touching any wiring. Label all low-voltage wires before disconnecting. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter. Check for short circuits in the low-voltage wiring before installing the new transformer — a wiring short is the #1 cause of repeat transformer failure.
• Warranty: 1-year OEM factory warranty. In-stock and ships same business day from our warehouse.

Compatibility: Direct OEM replacement for Carrier model UPFLOW250U12020AL upflow gas furnace. Verify the 120V primary and 24V/12V secondary voltage ratings on your unit's data plate before ordering. Have a question about fitment? Our HVAC parts specialists verify compatibility before you buy — call or chat today.