OEM Carrier Furnace Transformer 120V–24V 40VA for Model PG8MAA048090AAJA (Replaces HT01BC116)

This OEM step-down transformer is the factory-specified replacement for the Carrier PG8MAA048090AAJA gas furnace. The transformer converts 120V line voltage down to 24V AC, powering the entire low-voltage control circuit — including your thermostat, gas valve, inducer relay, and control board communication. When this transformer fails, nothing in the furnace responds: the thermostat calls for heat but the board receives no 24V signal, resulting in a completely dead furnace with no ignition attempt, no inducer start, and no error codes. A failed transformer is also frequently caused by a short elsewhere in the low-voltage wiring — always inspect the wiring harness before replacing.

• Specs: Primary Voltage: 120V AC | Secondary Voltage: 24V AC | VA Rating: 40VA | Frequency: 60 Hz | Phase: Single | Mounting Type: Foot-mount | Replaces OEM Part# HT01BC116 (superseded by HT680054)
• OEM vs Generic: OEM transformers are wound to exact factory VA tolerances, ensuring stable 24V output under full control-circuit load. Generic transformers often run hotter and may sag voltage under peak demand, causing intermittent lockouts and premature control board failure.
• Install Difficulty: 2/5 — Shut off power at the breaker and confirm zero voltage before touching any wiring. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter (check C–R terminals for 24V after install). Photograph or label all wire connections before removing the old transformer. Before powering up, verify no low-voltage short exists (check for <1 ohm between R and C on the wiring harness).
• Warranty: 1-year OEM manufacturer warranty. Ships same business day from our warehouse when ordered before 3 PM local time.

Compatibility: Fits Carrier model PG8MAA048090AAJA gas furnace. This part supersedes OEM part number HT01BC116; the current shipping part number is HT680054. Both are the identical 120V–24V 40VA transformer — fully interchangeable. Verify your unit's data plate voltage before ordering. Need fitment confirmation? Our HVAC parts team checks compatibility before you buy — reach out before placing your order.