OEM Carrier Furnace Transformer 120V–24V 40VA for Model PG9MAB048080AASA (HT01BC116 / HT680054)

This OEM step-down transformer is the factory-specified replacement for the Carrier PG9MAB048080AASA gas furnace. It converts 120V AC line voltage down to 24V AC to power the furnace's entire low-voltage control circuit — including the thermostat, control board, gas valve, and ignition system. When the transformer fails, the furnace goes completely silent: no inducer, no spark, no heat. If you're reading 0V between the R and C terminals on your control board, a failed transformer is the first thing to rule out.

• Specs: Input Voltage: 120V AC | Output Voltage: 24V AC | VA Rating: 40VA | Frequency: 60Hz | Connection: Wire leads with foot mount | Includes integrated 3A fuse protection
• OEM vs Generic: This OEM unit is wound to exact factory VA and voltage tolerances. Generic transformers frequently run off-spec voltage output, causing nuisance lockouts, erratic thermostat behavior, and premature control board failure — a far more expensive repair.
• Install Difficulty: 2/5 — Shut off power at the breaker before starting. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter. Label or photograph all wire connections before disconnecting the old unit. Verify 24V output at R–C terminals after installation to confirm correct operation.
• Warranty: 1-year OEM manufacturer warranty. Ships same business day from our stocked warehouse.

Compatibility Note: Designed for Carrier model PG9MAB048080AASA gas furnaces. OEM part number HT01BC116 has been superseded by HT680054 — both are the same factory-spec 120V–24V 40VA unit. Also cross-references: HT01BC115, HT01BB126, HT01BC120, HT01AW115, and 322666-701. Confirm your unit's control voltage on the data plate before ordering. Our fitment team is available to verify compatibility prior to purchase.