OEM Carrier 40VA Control Transformer HT01BC116 for Model GA1AAD042070AAJA

This OEM Carrier control transformer (part number HT01BC116) is the factory-specified replacement for the GA1AAD042070AAJA packaged gas/electric unit. The transformer steps down 120V line voltage to the 24V AC signal that powers your thermostat, control board, contactor coil, and all low-voltage control circuits. When this transformer fails, absolutely nothing will respond — the thermostat goes blank, the system won't call for heat or cooling, and no fault codes will display because the control board itself has lost power. A blown transformer is often caused by a shorted low-voltage wire or a failed component drawing excess current; always inspect the low-voltage circuit before replacing.

• Specs: 40VA rating | Primary: 120V AC | Secondary: 24V AC | OEM part number HT01BC116 | Factory-matched output for Carrier low-voltage control circuits
• OEM vs Generic: This is a genuine OEM Carrier transformer built to exact VA and voltage tolerances. Generic transformers often underperform under sustained load, causing intermittent lockouts, nuisance tripping, or premature control board failure due to voltage fluctuations.
• Install difficulty: 2/5 — Disconnect power at the breaker before beginning. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter (to verify 24V output after install). Label all low-voltage wires before disconnecting and inspect for shorts that may have caused original failure.
• Warranty: 1-year OEM factory warranty against defects. Orders placed before cutoff ship same business day from our stocked warehouse.

Compatibility: Designed specifically for the Carrier GA1AAD042070AAJA packaged unit. Verify your existing transformer's VA rating and primary/secondary voltage on the unit data plate before ordering. If you're unsure of fitment, our HVAC parts specialists are available to confirm compatibility before you purchase — no guesswork needed. In stock and ready to ship today.