OEM Carrier Transformer 40VA 120V to 24V for Model FV4CNB005T00ABAA

This OEM replacement transformer (part number HT01CN236) is the factory-specified control circuit transformer for the Carrier FV4CNB005T00ABAA fan coil air handler. The transformer steps down 120V line voltage to the 24V signal voltage required to power your thermostat, control board, and all low-voltage switching circuits. When this component fails, the result is typically a completely unresponsive system — the thermostat goes dark, the air handler won't respond to any calls for heating or cooling, and no control functions operate. A failed transformer is often misdiagnosed as a control board failure, making this an essential first diagnostic check.

• Specs: 40VA rated | Primary: 120V AC | Secondary: 24V AC | OEM part number HT01CN236 | Direct drop-in fit for Carrier FV4CNB005T00ABAA air handler
• OEM vs Generic: This OEM transformer is wound to exact factory VA ratings and insulation class, ensuring stable 24V output under full control circuit load. Generic transformers frequently run undervoltage under load, causing erratic contactor chatter, nuisance lockouts, and premature control board failure.
• Install difficulty: 2/5 — Disconnect power at the breaker before beginning. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter. Note wire colors and terminal positions before removing the old unit. Verify 24V output at secondary terminals before reassembling the panel.
• Warranty: 1-year OEM factory warranty against defects in materials and workmanship. In stock and ships same business day from our warehouse.

Compatibility: Designed specifically for the Carrier FV4CNB005T00ABAA fan coil air handler. Confirm your existing transformer's VA rating and primary/secondary voltages on the unit data plate or old transformer label before ordering. Our HVAC parts specialists are available to verify fitment — order with confidence and get back to comfort fast.