OEM Carrier Control Transformer 120V–24V 40VA for Model PG8DAA024070AAJA (HT01BC116 / HT680054)

This OEM step-down transformer is the factory-specified replacement for the Carrier PG8DAA024070AAJA gas furnace. It converts 120V line voltage to the 24V AC signal that powers every low-voltage control circuit in your system — including the thermostat, gas valve, inducer relay, and control board. When the transformer fails, the entire low-voltage circuit goes dead: the thermostat goes blank, the furnace won't respond to a call for heat, and nothing in the system operates. A quick check with a multimeter between the R and C terminals on the control board (expecting ~24–28V AC) will confirm whether the transformer is the culprit.

• Specs: Primary Voltage: 120V AC | Secondary Voltage: 24V AC | VA Rating: 40VA | Frequency: 60 Hz | Phase: Single | Mounting: Foot-mount with wire leads
• OEM vs Generic: This is a genuine OEM Carrier replacement (updated part number HT680054, superseding original HT01BC116). OEM units are wound to exact VA and voltage tolerances. Generic transformers frequently run outside rated output voltage, which can damage sensitive control boards and void equipment warranties.
• Install Difficulty: 2/5 — Shut off power at the breaker and verify voltage is absent before touching any wiring. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter. Photograph all wire connections before disconnecting. Reconnect wire leads to the same terminals as the original and restore power to test.
• Warranty: 1-year OEM manufacturer warranty. In-stock units ship same business day from our warehouse when ordered before cutoff.

Compatibility: Direct OEM replacement for Carrier model PG8DAA024070AAJA gas furnace. This part (HT680054) is the current superseding OEM part number for the original HT01BC116 and cross-references a wide range of Carrier, Bryant, and Payne furnace models. Always verify your unit's wiring diagram and data plate voltage ratings before installing. Need help confirming fitment? Our HVAC parts specialists are standing by — order with confidence and we'll ship today.