OEM Carrier 40VA Transformer 120V–24V (HT01BC116) for Model PG8DAA036070ADJA

This OEM 40VA step-down transformer is the factory-specified control-circuit transformer for the Carrier PG8DAA036070ADJA gas furnace. Its sole job is to convert 120V line voltage down to 24V AC so that every low-voltage component in your system — thermostat, gas valve, inducer relay, and control board — has a clean, stable power supply. When this transformer fails, the entire control circuit goes dark: your thermostat won't communicate, the furnace won't attempt a heat call, and nothing responds. A failed transformer is often misdiagnosed as a bad control board, making this an important first-check before replacing more expensive components.

• Specs: Input 120V AC | Output 24V AC | 40VA rating | 60Hz single-phase | Foot-mount configuration | Wire-lead connections
• OEM vs Generic: OEM transformers are wound to exact factory VA tolerances, protecting downstream components (gas valve coils, control boards) from undervoltage or surge damage. Generic units often fall short on VA capacity under load, causing intermittent low-voltage faults and premature control board failure.
• Install Difficulty: 2/5 — Shut off power at the breaker and verify 0V with a multimeter before touching any wiring. Tools needed: flathead and Phillips screwdrivers, multimeter, needle-nose pliers. Photograph all wiring before disconnecting. Replacement typically takes 20–30 minutes.
• Warranty & Shipping: 1-year OEM manufacturer warranty. In stock — ships same business day from our warehouse.

Compatibility: Factory-specified replacement for Carrier model PG8DAA036070ADJA gas furnaces. Note: OEM part HT01BC116 has been superseded by updated part number HT680054 — both are genuine Carrier OEM and are direct drop-in replacements for this unit. Verify your existing transformer's input voltage and VA rating on the data plate before ordering. Have questions about fitment? Our HVAC parts specialists confirm compatibility before you order — reach out today.