OEM Carrier Furnace Control Transformer 120V–24V 40VA for Model PG8JAA066135ABJA

This OEM Carrier control transformer (part number HT01BC116, superseded by HT680054) is the factory-specified step-down transformer for the Carrier PG8JAA066135ABJA gas furnace. It converts 120V line voltage to the 24V AC signal that powers the entire low-voltage control circuit — including the thermostat, gas valve, inducer relay, and control board. When this transformer fails, the furnace loses all 24V control power: nothing responds, nothing lights up, and no fault codes appear. Before replacing boards or valves, always verify the transformer output with a multimeter.

• Specs: 120V primary | 24V secondary | 40VA rating | Wire lead connections | Factory OEM tolerances | Direct OEM part — supersedes HT01BC116
• OEM vs Generic: OEM transformers are wound to exact VA and voltage tolerances required by Carrier's control board. Undersized or off-spec generic transformers can cause nuisance lockouts, board brownouts, and premature contactor failure.
• Install difficulty: 2/5 — Shut off power at the disconnect and breaker before beginning. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter (to verify 24V output after install). Label or photograph existing wire connections before removal.
• Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Designed for the Carrier PG8JAA066135ABJA gas furnace. Also fits a wide range of Carrier, Bryant, and Payne furnace models requiring a 120V–24V 40VA step-down control transformer. Always verify your existing transformer's primary voltage, secondary voltage, and VA rating on the data plate before ordering. Have a fitment question? Our HVAC parts team confirms compatibility before you buy.