OEM Carrier Control Transformer 120V to 24V 40VA — HT01CN001 for Model UPFLOW100U4819A

This is the factory OEM replacement control transformer for the Carrier UPFLOW100U4819A upflow gas furnace. The transformer steps down 120V line voltage to the 24V used by the low-voltage control circuit — powering the thermostat, control board signals, and every safety relay in the system. When it fails, the entire control circuit goes dark: the thermostat loses power, the furnace will not respond to a call for heat, and no fault codes will appear because the board itself has no power. Replacing this transformer is often the fastest and most cost-effective fix when the system is completely unresponsive.

• Specs: 120V primary | 12/24V secondary | 40VA rated | Factory OEM part number HT01CN001 | Direct drop-in replacement for Carrier UPFLOW100U4819A
• OEM vs Generic: OEM transformers are wound to exact VA and voltage tolerances required by the Carrier control board. Undersized or off-tolerance aftermarket units can cause nuisance tripping, board damage, or unsafe operation — always match factory specs on a control transformer.
• Install difficulty: 2/5 — Turn off all power at the disconnect and breaker before proceeding. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter (to confirm 0V before touching terminals). Label all wiring before disconnecting. Confirm 24V output with a meter before reassembly.
• Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Engineered specifically for the Carrier UPFLOW100U4819A upflow furnace. Verify your existing transformer reads 120V primary and 24V/40VA secondary on the data plate or unit wiring diagram before ordering. Cross-references include legacy Carrier part numbers HT01BJ115, 19EA41612, and 19EA42612. Our fitment team is available to verify compatibility before you order — don't hesitate to reach out.