OEM Carrier Transformer 40VA 120V/24V for Model GB1AAV036090AAJA

This is the factory OEM replacement transformer (part# HT01BC116) for the Carrier GB1AAV036090AAJA gas furnace. The transformer steps down line voltage from 120V to the 24V AC signal that powers your thermostat, control board, gas valve, and all low-voltage control circuits. When the transformer fails, the entire control circuit goes dead — the thermostat goes blank, the furnace won't respond to any call for heat or cooling, and nothing in the system initializes. It's one of the most commonly overlooked failure points during a no-power diagnostic.

• Specs: 40VA rating | 120V primary / 24V secondary | OEM part number HT01BC116 | Factory-matched output for Carrier low-voltage control circuits
• OEM vs Generic: The OEM HT01BC116 transformer is wound to Carrier's exact VA and voltage tolerances, ensuring stable 24V output under full control circuit load. Undersized generic transformers can sag below 24V under load, causing erratic board behavior, nuisance lockouts, or premature control board failure.
• Install difficulty: 2/5 — Shut off power at the breaker and confirm voltage is zero with a multimeter before proceeding. Tools needed: flathead and Phillips screwdrivers, multimeter, wire nuts or spade connectors. Note primary and secondary wire positions before disconnecting. Total job time is typically 20–30 minutes.
• Warranty: 1-year OEM factory warranty against defects. In-stock and ships same business day from our warehouse.

Compatibility: Designed as the direct OEM replacement for the Carrier GB1AAV036090AAJA gas furnace. Confirm your existing transformer is rated 40VA 120V/24V by checking the data label on the transformer body before ordering. If you're unsure of fitment, our parts team verifies compatibility before your order ships — no guesswork required.