OEM Carrier Furnace Control Transformer 120V–24V 40VA for Model PG8JAA042090ADJA

This is the OEM factory-specified control transformer for the Carrier PG8JAA042090ADJA gas furnace, referenced under part number HT01BC116. The transformer is the backbone of your furnace's low-voltage control circuit — it steps down 120V line voltage to the 24V signal that powers your thermostat, gas valve, inducer relay, and control board. When this transformer fails, the entire control circuit goes dark: you'll see a completely unresponsive furnace with no thermostat display, no inducer startup, and no fault codes. A failed transformer is often confirmed with a multimeter — zero volts on the secondary side (24V terminals) with power present on the primary side (120V) means replacement is needed immediately.

• Specs: Primary Voltage: 120V | Secondary Voltage: 24V | VA Rating: 40VA | Class 2 step-down transformer | Wire lead connections | Factory-matched to Carrier PG8JAA042090ADJA
• OEM vs Generic: OEM transformers are wound and tested to exact Carrier specifications. Generic units often use thinner gauge windings that overheat under sustained load, causing premature failure and potentially damaging downstream components like the control board or gas valve.
• Install Difficulty: 2/5 — Shut off power at the breaker before beginning. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter. Photograph all wire connections before removing old transformer. Confirm 24V output after installation before closing the furnace cabinet.
• Warranty: 1-year OEM manufacturer warranty. In-stock and ships same business day from our warehouse.

Compatibility: Designed as the direct OEM replacement for Carrier model PG8JAA042090ADJA gas furnaces. Note: HT01BC116 has been superseded — our listing supplies the current authorized OEM replacement (HT680054) which is a direct drop-in at the same 120V/24V/40VA spec. Verify your existing transformer's primary voltage and VA rating on its label before ordering. Questions about fitment? Our HVAC parts specialists confirm compatibility before you buy.