OEM Carrier Transformer 40VA 120V to 24V for Model FIOP100E301GA

This is the genuine OEM replacement transformer (part number HT01BD209) for the Carrier FIOP100E301GA fan coil or air handler unit. The transformer steps down 120V line voltage to the 24V AC signal that powers your entire control circuit — including the thermostat, relays, and control board. When this component fails, the result is total system unresponsiveness: your thermostat goes blank, no relays click, and nothing happens when you call for heating or cooling. A failed transformer is one of the most common and often overlooked causes of a completely dead HVAC system.

• Specs: 40VA rating | Primary: 120V AC | Secondary: 24V AC | OEM part number HT01BD209 | Factory-matched to Carrier FIOP100E301GA electrical specifications
• OEM vs Generic: This factory OEM transformer is wound to exact Carrier voltage and VA specifications. Generic aftermarket transformers often fall short on VA capacity, causing nuisance trips, brownouts on the control circuit, or premature failure under normal load — especially in multi-zone systems.
• Install Difficulty: 2/5 — Disconnect power at the breaker before beginning. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter. Verify 0V at primary terminals before handling. Label all wire connections before removal. Most installs take under 30 minutes.
• Warranty: 1-year OEM factory warranty against defects in materials and workmanship. Ships same business day from our climate-controlled warehouse.

Compatibility: Designed specifically for the Carrier FIOP100E301GA. Before ordering, confirm the VA rating and primary/secondary voltages on your existing transformer's label match. If your system has a secondary fuse or circuit breaker on the 24V side, inspect and replace it at the same time — a shorted control component may have caused the original transformer failure. Our parts specialists are available to verify fitment before you order. In stock and ships today.