OEM Carrier Furnace Transformer 120V–24V 40VA for Model PG8MAA048135ABJA

This OEM step-down transformer is the factory-specified control circuit transformer for the Carrier PG8MAA048135ABJA gas furnace. It converts 120V line voltage to the 24V AC signal that powers your thermostat, gas valve, control board, and all low-voltage components. When the transformer fails, the entire control circuit goes dead — the furnace will not respond to any thermostat call, and nothing will happen on a call for heat or cooling. A failed transformer is often identified by checking for 24V between the R and C terminals on the control board; a reading of 0V with line power confirmed is a clear sign of transformer failure.

• Specs: Input: 120V AC | Output: 24V AC | VA Rating: 40VA | Mounting: Foot mount | Connection: Wire leads | Frequency: 60 Hz
• OEM vs Generic: This is a genuine OEM Carrier replacement (current superseding part number HT680054), supplied in a factory-authorized parts box. Generic transformers often have imprecise VA ratings and ill-fitting mounting tabs — one customer noted a generic unit required modification to mount correctly. OEM guarantees a direct drop-in fit and proper output voltage under load.
• Install difficulty: 2/5 — Shut off power to the furnace at the breaker and disconnect the 120V feed before touching any wiring. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter (to confirm 0V before touching terminals and verify 24V output after installation). Photograph all wire connections before disconnecting.
• Warranty: 1-year OEM factory warranty. Ships same business day from our warehouse.

Compatibility: Direct OEM replacement for Carrier model PG8MAA048135ABJA gas furnaces. OEM part number HT01BC116 has been superseded by HT680054 — both are the same factory-spec 120V–24V 40VA transformer. Also cross-references: HT01BC115, HT01BC120, HT01BB126, B1810113, and 322666-701. Verify your existing transformer's input voltage, output voltage, and VA rating against your unit's data plate before ordering. Need fitment confirmation? Our team is happy to verify compatibility before you buy — order today and receive same-day shipping.