OEM Carrier Furnace Transformer 120V–24V 40VA for Model PG9MAA048100AFKA (Part# HT01BC116 / HT680054)

This is the OEM factory-specified step-down control transformer for the Carrier PG9MAA048100AFKA gas furnace. The transformer converts 120V line voltage to the 24V AC signal that powers every low-voltage component in your system — thermostat, gas valve, inducer relay, and control board. When this transformer fails, the furnace goes completely silent: the thermostat shows no response, the board has no power, and nothing turns on. It is one of the most commonly overlooked root causes of a total no-heat call. OEM part number HT01BC116 has been superseded by the current factory-authorized replacement, HT680054, which ships in a Carrier-branded box and is a direct drop-in swap.

• Specs: Primary Voltage: 120 VAC | Secondary Voltage: 24 VAC | VA Rating: 40VA | Frequency: 50/60 Hz | Phase: Single | Dimensions: 3" L × 2-2/16" W × 2" H | Foot-mount configuration | Wire lead connections
• OEM vs Generic: This OEM transformer is wound and tested to Carrier's exact VA and voltage-drop tolerances. Generic transformers often run high secondary voltage at light load, which can damage sensitive control boards and shorten thermostat life. OEM is always the correct choice for PG9MAA-series furnaces.
• Install difficulty: 2/5 — Shut off power at the breaker and confirm zero voltage before touching any wiring. Tools needed: flathead and Phillips screwdriver, 1/4" nut driver, multimeter. Always label or photograph all wire connections before removal. Verify 24V output across R and C terminals after installation to confirm function before closing the cabinet.
• Warranty: 1-year OEM manufacturer's warranty. In-stock and ships same business day when ordered by cutoff time.

Compatibility: Designed for the Carrier PG9MAA048100AFKA gas furnace. Also replaces legacy part numbers HT01BC115, HT01BB126, HT01CT120, HT01BC120, HT01AW115, HT01AA012, HT01AQ110, HT01CT210, 322666-701, 322953-302, and B1810113 across Carrier, Bryant, and Payne furnace platforms. Always confirm primary/secondary voltage and VA rating on your unit's data plate before ordering. Need fitment verification? Our HVAC parts team confirms compatibility before you buy — reach out before placing your order.