OEM Carrier Control Transformer 120V to 24V 40VA for Model U19X100U36A

This OEM Carrier transformer (part #HT01CN001) is the factory-specified replacement for the Carrier U19X100U36A HVAC system. The transformer steps down 120V line voltage to a safe 24V (with a 12V tap) at 40VA to power all low-voltage control circuits — including the thermostat, control board signals, and relay coils. When it fails, the entire control circuit goes dark: the thermostat loses power, the system refuses to respond to any command, or you may detect a faint buzzing or burning smell near the air handler cabinet.

• Specs: 120V Primary | 24V / 12V Secondary | 40VA Rating | OEM Part #HT01CN001 | Replaces legacy part numbers HT01BJ115, 19EA41612, and 19EA42612
• OEM vs Generic: This is the genuine Carrier factory part — not an aftermarket substitute. OEM transformers are wound to exact VA and voltage tolerances, ensuring your control board and thermostat operate within safe design parameters. Generic alternatives can run outside tolerance, causing nuisance trips or premature board failure.
• Install difficulty: 3/5 — Requires disconnecting 120V line power at the breaker before any work begins. Tools needed: multimeter (to confirm 0V before touching terminals), flat-head and Phillips screwdrivers, wire stripper, needle-nose pliers, and wire nuts or terminal connectors. Always label or photograph all low-voltage wiring before disconnecting. Verify secondary output voltage after installation before restoring full system power.
• Warranty: 1-year OEM factory warranty. Ships same business day from our warehouse on all in-stock orders placed before cut-off.

Compatibility: Factory-matched for Carrier model U19X100U36A. Confirm your existing transformer's primary voltage (120V), secondary voltage (24V/12V), and VA rating (40VA) against your unit's data plate before ordering — incorrect VA ratings can overload the transformer under full control-circuit load. Have a question about fitment? Our HVAC parts specialists verify compatibility before you order.