OEM Carrier 40VA Control Transformer HT01BC116 for Model PG8UAA042091AAJA

This OEM replacement control transformer (part# HT01BC116) is the factory-specified unit for the Carrier PG8UAA042091AAJA gas furnace. The transformer steps down 120V line voltage to the 24V AC signal that powers your thermostat circuit, control board, gas valve, and all low-voltage safety controls. When it fails, the entire control circuit goes dark — nothing responds, no heat is called, and the system appears completely dead. A blown fuse on the transformer secondary side is often the first symptom before full failure.

• Specs: 40VA rating | 120V primary / 24V secondary | OEM factory-matched output tolerance | Replaces OEM part number HT01BC116
• OEM vs Generic: OEM transformers are wound and potted to Carrier's exact VA and impedance spec. Under-rated generic units overheat under full 24V load (gas valve + board + thermostat simultaneously), leading to premature failure or nuisance fuse trips.
• Install difficulty: 2/5 — Shut off power at the disconnect before beginning. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter to confirm 24V output after install. Label all wiring before disconnecting. Always replace the control board fuse if it was blown prior to transformer failure.
• Warranty: 1-year OEM factory warranty. In-stock and ships same business day from our warehouse.

Compatibility: Engineered specifically for the Carrier PG8UAA042091AAJA packaged gas furnace. Always verify your existing transformer's VA rating and primary/secondary voltages against your unit's data plate before ordering. Need help confirming fitment? Our HVAC parts team is ready to verify compatibility before you purchase.