OEM Carrier 40VA Control Transformer 120V–24V for Model PG8JAA036045ABJA

This is the factory-specified OEM control circuit transformer for the Carrier PG8JAA036045ABJA 80% AFUE gas furnace. The transformer steps down the 120V line voltage to the 24V AC required to power the thermostat, control board, gas valve, and all low-voltage components. When this transformer fails, the entire control circuit goes dead — you'll see a blank thermostat display, no response to any call for heat or cooling, and potentially a completely silent system with no error codes. This part ships under OEM part number HT01BC116, now fulfilled as updated replacement HT680054, and is a factory-authorized direct swap.

• Specs: 40VA rating | Primary input: 120V AC | Secondary output: 24V AC | 60Hz | Foot-mount configuration | Wire lead connections
• OEM vs Generic: OEM transformers are wound to exact VA tolerances, protecting downstream low-voltage components like the control board and gas valve from voltage fluctuation. Generic units often run under-rated, causing nuisance tripping, premature board failure, or repeated transformer burnout — especially when multiple 24V accessories (humidifiers, zoning) are on the same circuit.
• Install difficulty: 2/5 — Always disconnect power at the breaker before beginning. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter (to verify 0V before touching terminals). Photograph all wire connections before disconnecting. Match wire leads carefully: primary wires to line voltage, secondary wires to 24V control terminals. Note: if the replacement transformer fails again quickly, suspect a short in the 24V wiring before installing.
• Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Engineered for the Carrier PG8JAA036045ABJA 80% AFUE gas furnace and cross-compatible with multiple Bryant, Carrier, and Payne furnace models sharing the 40VA 120V/24V transformer specification. Supersedes legacy part numbers HT01BC116, HT01BC115, HT01BB126, HT01BC120, and others. Verify your unit's data plate voltage requirements before ordering — our fitment team is available to confirm compatibility before you buy.