OEM Carrier Transformer 40VA 120V/24V Control Circuit for Model FPAA125D34CN

This OEM Carrier transformer (part number HT01BC116) is the factory-specified step-down transformer for the Carrier FPAA125D34CN packaged unit. It converts 120V line voltage down to 24V AC to power the entire low-voltage control circuit — including the thermostat, contactor coil, and control board. When this transformer fails, the result is a completely unresponsive system: the thermostat goes dark, no calls for heating or cooling are processed, and the unit will not energize under any mode. It is often the first component to inspect when a system shows zero control-side activity.

• Specs: 40VA rated | 120V primary input | 24V secondary output | Class 2 control transformer | Compact footprint for direct OEM fit
• OEM vs Generic: This OEM unit is wound and rated to exact Carrier factory specifications, ensuring stable 24V output under full control-circuit load. Generic transformers frequently under-deliver VA capacity, causing voltage sag that leads to erratic contactor chatter, board faults, and premature component failure.
• Install difficulty: 2/5 — Disconnect power at the breaker and verify voltage absence with a multimeter before beginning. Tools needed: flathead and Phillips screwdrivers, wire nuts or spade connectors, multimeter. Label or photograph all wiring connections prior to removal. Verify 24V output at secondary terminals after installation before restoring full power.
• Warranty: 1-year OEM factory warranty. Orders ship same business day from our stocked warehouse when placed before cutoff.

Compatibility: Designed as a direct OEM replacement for the Carrier FPAA125D34CN packaged unit. Always confirm the existing transformer's VA rating, primary voltage, and secondary voltage on your unit's data plate or wiring diagram before ordering to ensure proper fitment. Our parts specialists are available to verify compatibility before you purchase — call or chat today. In stock and ships today.