OEM Carrier Furnace Transformer 120V to 24V 40VA — Model UPFLOW100U4219A

This is the genuine OEM Carrier transformer (part number HT01CN001), factory-specified for the UPFLOW100U4219A upflow furnace. The transformer steps down 120V line voltage to a safe 24V (with 12V secondary tap) to power all low-voltage control circuits — including the thermostat, control board relay coils, and zone valves. At 40VA, it delivers sufficient capacity for multi-stage systems. When this transformer fails, the entire control circuit loses power: the thermostat goes blank, the furnace will not respond to any call for heat, and diagnostics cannot run. Common causes of failure include voltage surges, short circuits in low-voltage wiring, and age-related winding breakdown.

• Specs: 120V primary | 24V / 12V secondary | 40VA rated | Factory-matched Carrier OEM replacement | Replaces legacy part numbers HT01BJ115, 19EA41612, 19EA42612
• OEM vs Generic: The OEM HT01CN001 is wound to exact Carrier factory tolerances, ensuring stable 24V output under full load. Generic aftermarket transformers may under-deliver on VA capacity, causing nuisance brownouts and premature control board failure.
• Install Difficulty: 2/5 — Shut off power at the disconnect and breaker before starting. Tools needed: flathead and Phillips screwdrivers, multimeter (to confirm 24VAC output after install), wire stripper/connectors if needed. Label all low-voltage wires before disconnecting. Confirm no short circuits in the 24V wiring loop before energizing, or the new transformer may fail immediately.
• Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Engineered as a direct OEM replacement for the Carrier UPFLOW100U4219A upflow furnace. Verify part number and voltage rating on your unit's data label before ordering. Our technical team is available to confirm fitment — contact us before you buy if you have any questions. Order today and get same-day shipping on in-stock parts.