OEM Carrier 40VA Control Transformer for Model G1RS125A20 — Part HT01BC116

This OEM replacement control transformer (part number HT01BC116) is the factory-specified unit for the Carrier G1RS125A20 furnace. The transformer steps down 120V line voltage to the 24V signal required by your thermostat, control board, gas valve, and all low-voltage control circuit components. When the transformer fails, the entire control circuit goes dark — the thermostat displays nothing, the system won't call for heat or cooling, and no diagnostic codes can be retrieved from the board. If your system is completely unresponsive despite confirmed line voltage at the unit, this transformer is the first component to test.

• Specs: 40VA rated | 120V primary / 24V secondary | Class 2 control circuit transformer | Direct OEM replacement for part HT01BC116
• OEM vs Generic: This is a genuine Carrier OEM transformer wound to exact VA and voltage tolerances. Generic transformers often under-deliver VA capacity, causing nuisance tripping of the built-in thermal fuse under normal load — a failure mode that can be mistaken for a bad control board.
• Install difficulty: 2/5 — Disconnect all power before servicing. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter (to confirm 0V before touching wiring). Label or photograph all low-voltage wiring connections before removal. The transformer mounts to the blower compartment panel with two screws.
• Warranty: 1-year OEM factory warranty. Orders placed before cutoff ship same business day from our stocked warehouse.

Compatibility: Engineered specifically for the Carrier G1RS125A20 gas furnace. Always verify transformer VA rating and primary/secondary voltages on your unit's wiring diagram before ordering. Our team is available to confirm fitment prior to purchase — never guess on a control circuit component.