OEM Carrier Furnace Transformer 40VA 120V-24V for Model PG9MAA036040AFKA

This OEM step-down transformer is the factory-authorized replacement for the Carrier PG9MAA036040AFKA gas furnace. The transformer converts 120V line voltage to the 24V AC signal that powers every low-voltage component in your system — thermostat, gas valve, control board relays, and zone controllers. When the transformer fails, the entire control circuit goes dark: your thermostat goes blank, the furnace won't respond to any call for heat, and you may measure zero voltage between the R and C terminals on the control board. Replacing it is one of the most cost-effective furnace repairs you can make.

• Specs: 40VA rating | 120V primary / 24V secondary | 60 Hz single-phase | Foot-mount configuration | Wire lead connections with insulated female quick-connects | Dimensions approx. 3″ L × 2-3/16″ W × 2″ H
• OEM vs Generic: This is a genuine OEM Carrier replacement (supersedes legacy part number HT01BC116 → current OEM part HT680054), supplied in factory-authorized packaging. Generic transformers frequently use undersized copper windings and run warmer under load, increasing the risk of premature failure and nuisance tripping of your furnace's limit circuit.
• Install difficulty: 2/5 — Shut off power at the disconnect and verify zero volts before touching any wiring. Photograph all wire connections before removal. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter. Verify 24V output across R and C terminals after installation before closing the unit.
• Warranty: 1-year OEM manufacturer warranty. Ships same business day from our warehouse when ordered by 5 PM local time.

Compatibility: Designed for the Carrier PG9MAA036040AFKA gas furnace. This transformer also carries crossover coverage for multiple Carrier, Bryant, and Payne furnace models — confirm your unit's data plate shows 120V primary / 24V secondary / 40VA before ordering. Not sure it fits? Our parts team verifies fitment at no charge before you buy.