OEM Carrier Furnace Control Transformer 40VA 120V–24V for Model PG8JAA024045AAJA

This is the factory-specified OEM step-down transformer for the Carrier PG8JAA024045AAJA gas furnace, sold under OEM part number HT01BC116 (current superseding OEM part: HT680054). The transformer is the heartbeat of your furnace's low-voltage control circuit — it steps 120V line power down to 24V AC to energize the thermostat, control board, gas valve, and every relay in the system. When it fails, nothing works: the thermostat goes blank, the system is completely unresponsive, and you may measure 0V between the R and C terminals on the control board. A blown fuse or shorted low-voltage wiring is often the root cause, so always inspect the wiring harness before condemning the transformer.

• Specs: 40VA capacity | 120V AC primary | 24V AC secondary | 50/60 Hz single-phase | Foot-mount bracket | Wire lead connections with insulated female quick-connects
• OEM vs Generic: OEM transformers are wound to exact VA tolerances, preventing nuisance overloads that trip thermal protection. Generic units frequently run under-rated VA, causing premature burnout — especially on systems with zone valves or multiple thermostats drawing continuous current.
• Install difficulty: 2/5 — Shut off the furnace disconnect and confirm 0V at the transformer primary before touching any wiring. Tools needed: multimeter, 1/4" nut driver, needle-nose pliers. Photograph all wiring connections before disconnecting. Check for a short on the 24V secondary circuit before energizing the new transformer.
• Warranty: 1-year OEM manufacturer warranty. In-stock units ship same business day from our warehouse when ordered by 5 PM local time.

Compatibility: Designed for the Carrier PG8JAA024045AAJA gas furnace. Also cross-references HT680054, HT01BC115, HT01BB126, HT01CT120, HT01BC120, and HT01AW115 — confirm your existing transformer's primary/secondary voltage and VA rating on its nameplate before ordering. Our parts specialists verify fitment at no charge — contact us before you order if you have any questions.