OEM Carrier Furnace Control Transformer 120V–24V 40VA for Model PG9MAA036040AEKA (HT01BC116 / HT680054)

This is the OEM factory-specified step-down control transformer for the Carrier PG9MAA036040AEKA gas furnace. The transformer converts 120V line voltage to 24V AC, powering every low-voltage control component in your system — the thermostat, control board, gas valve, and zone controls. When this transformer fails, the entire control circuit goes dead: you may see a blank thermostat display, no furnace response whatsoever, or a tripped 3A fuse on the board. Note: OEM part number HT01BC116 has been superseded by HT680054 — this is the current, factory-authorized replacement and is a direct drop-in with no modifications required.

• Specs: Primary voltage: 120V AC | Secondary voltage: 24V AC | VA rating: 40VA | Frequency: 50/60 Hz | Phase: Single | Mounting type: Foot mount with wire leads
• OEM vs Generic: OEM transformers from Carrier are wound to exact VA and voltage tolerances. Undersized or off-tolerance generic units can cause nuisance tripping, control board damage, or premature fuse failure — a risk not worth taking on a furnace control circuit.
• Install difficulty: 2/5 — Turn off power at the breaker and confirm 0V before touching any wiring. Photograph all wire connections before removal. Tools needed: flathead and Phillips screwdrivers, multimeter, needle-nose pliers. Check and replace the 3A low-voltage fuse on the control board if the original transformer failed due to a short.
• Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Designed for the Carrier PG9MAA036040AEKA gas furnace. This OEM part (HT01BC116, superseded by HT680054) also fits a wide range of Carrier, Bryant, and Payne furnace models sharing the 120V–24V 40VA transformer specification. Verify your existing transformer's primary/secondary voltage and VA rating against your unit's data plate before ordering. Have questions about fitment? Our HVAC parts team confirms compatibility before you buy — order with confidence and get it shipped today.