OEM Carrier 40VA Control Transformer HT01BC116 for Model GB3AAV048115AGJA

This OEM replacement transformer (part number HT01BC116) is the factory-specified control circuit transformer for the Carrier GB3AAV048115AGJA gas furnace. Its sole job is to step down 120V line voltage to the 24V signal voltage that powers your thermostat, control board, gas valve, and every other low-voltage component in the system. When the transformer fails, absolutely nothing works — the thermostat goes blank, the furnace won't respond to any call for heat or cooling, and there are no fault codes because the board itself has no power. If you've confirmed 120V at the primary side but zero voltage at the secondary, this transformer is your fix.

• Specs: 40VA rating | Primary: 120V | Secondary: 24V | OEM part number HT01BC116 | Factory wire lead configuration matches original installation
• OEM vs Generic: This is the factory OEM unit built to Carrier's exact VA rating and insulation class. Undersized generic transformers frequently fail under peak load — especially in multi-stage or communicating systems — causing repeated nuisance lockouts and premature control board damage.
• Install difficulty: 2/5 — Disconnect power at the breaker and verify zero voltage before handling. Tools needed: flathead and Phillips screwdrivers, multimeter, wire stripper. Match wire colors carefully; photograph existing connections before removal. The transformer typically mounts to the blower deck or control panel with two screws.
• Warranty: 1-year OEM factory warranty. In-stock units ship same business day when ordered before 3PM local time.

Compatibility: Engineered specifically for the Carrier GB3AAV048115AGJA gas furnace. Always confirm the VA rating and primary/secondary voltage on your existing transformer's label before ordering to ensure a direct fit. Our HVAC parts specialists are available to verify compatibility before you purchase — no guesswork required.