OEM Carrier Furnace Transformer 120V–24V 40VA for Model PG8JAA042090ACJA

This OEM step-down transformer is the factory-specified replacement for the Carrier PG8JAA042090ACJA gas furnace. It converts 120V line voltage down to 24V AC to power all low-voltage control circuit components — including the thermostat, gas valve, inducer relay, and control board. When the transformer fails, the entire low-voltage control circuit goes dead: the thermostat display may go blank, the furnace won't respond to any call for heat, and nothing in the system will energize. OEM part number HT01BC116 has been superseded by the current authorized replacement HT680054, which is a drop-in, factory-authorized upgrade shipped in a Carrier factory parts box.

• Specs: 120V primary | 24V secondary | 40VA rating | 50/60 Hz | Single phase | Foot-mount | Wire lead connections
• OEM vs Generic: OEM transformers are wound to exact factory VA and voltage tolerances. Generic units can deliver fluctuating secondary voltage that stresses control boards and shortens the life of downstream low-voltage components.
• Install difficulty: 2/5 — Shut off power at the breaker before starting. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter. Measure 24V output across the R and C terminals on the control board to confirm the old transformer has failed before replacing. Always photograph all wiring connections before disconnecting leads.
• Warranty: 1-year OEM factory warranty. In-stock and ships same business day from our warehouse.

Compatibility: Direct OEM replacement for Carrier model PG8JAA042090ACJA gas furnace. This part supersedes HT01BC116, HT01BC115, HT01BC120, HT01BB126, and related legacy part numbers. Verify 120V primary and 24V/40VA secondary on your unit's data plate before ordering. Need help confirming fitment? Our HVAC parts specialists will verify compatibility before you buy — order today and get same-day shipping.