OEM Carrier 40VA Transformer 120V to 24V for Model U19X100U48A — Part# HT01CN001

This is the factory OEM replacement control transformer for the Carrier U19X100U48A, part number HT01CN001. The transformer steps down 120V line voltage to a safe 24V (12/24V secondary) to power the low-voltage control circuit — including your thermostat, contactor coil, and control board logic. When this transformer fails, the entire control circuit goes dead: the thermostat displays nothing, the system refuses to respond to any command, and you may detect a burning smell or audible buzzing near the air handler or furnace cabinet.

• Specs: 40VA rating | 120V primary | 12V / 24V secondary | Direct OEM drop-in replacement for Carrier U19X100U48A | Replaces legacy part numbers HT01BJ115, 19EA41612, 19EA42612
• OEM vs Generic: OEM transformers are wound to exact VA and voltage tolerances required by Carrier's control board. Undersized or off-tolerance generic units risk nuisance tripping, control board damage, and shortened system life.
• Install difficulty: 2/5 — Always shut off power at the disconnect and breaker before beginning. Tools needed: flathead and Phillips screwdrivers, multimeter (verify 0V before touching wiring), wire stripper, and needle-nose pliers. Photograph all wiring connections before removing the old transformer. Verify secondary voltage output with a multimeter after installation before restoring full power.
• Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Designed as an exact OEM replacement for Carrier model U19X100U48A. Always confirm the part number on your existing transformer's label and verify primary/secondary voltage ratings on your unit's data plate before ordering. Need help confirming fitment? Our HVAC parts specialists are standing by to verify compatibility before you buy — same-day shipping guaranteed on all in-stock orders.