OEM Carrier 40VA Step-Down Transformer 120V–24V for Model PG8DAA036070ABJA

This OEM step-down transformer is the factory-specified replacement for the Carrier PG8DAA036070ABJA gas furnace. The transformer converts 120V line voltage down to 24V AC to power all low-voltage control circuit components — including the thermostat, control board, gas valve, and inducer relay. When the transformer fails, the entire control circuit goes dead: the thermostat goes blank, the furnace won't respond to any call for heat, and no fault codes will appear on the control board because there is no power to drive them. If you measure 0V between the R and C terminals on your control board, a failed transformer is the most likely culprit.

• Specs: Input: 120V AC | Output: 24V AC | VA Rating: 40VA | Mounting Type: Foot mount | Connection: Wire leads with insulated female connectors | OEM Part: HT01BC116 (superseded by HT680054)
• OEM vs Generic: This OEM-spec transformer is wound to exact Carrier factory tolerances, ensuring stable 24V output under full load. Generic transformers can sag below 24V when the control circuit is fully loaded, causing intermittent lockouts, nuisance trips, and premature control board failure.
• Install Difficulty: 2/5 — Turn off the furnace disconnect switch and confirm voltage is zero before proceeding. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter. Photograph existing wiring connections before removing the old transformer. Reconnect leads to matching terminals and verify 24V output at R–C before restoring power.
• Warranty: 1-year OEM manufacturer warranty. In stock and ships same business day from our warehouse.

Compatibility: Designed for the Carrier PG8DAA036070ABJA gas furnace. This part also cross-references to Bryant, Payne, and ICP family furnaces sharing the same 120V–24V 40VA transformer specification. Always verify your existing transformer's input voltage, output voltage, and VA rating on the unit data plate before ordering. Our team is available to confirm fitment — just reach out before you order.