OEM Carrier 40VA Control Transformer HT01CN241 for Model FB4CNFS24L00ADAA

This OEM replacement transformer (part number HT01CN241) is the factory-specified control circuit transformer for the Carrier FB4CNFS24L00ADAA fan coil air handler. The transformer steps down line voltage from 120V to the 24V AC signal that powers your thermostat, control board, and all low-voltage switching circuits. When the transformer fails, nothing works — the thermostat goes dark, the system won't respond to calls for heating or cooling, and the control board loses all power. A failed transformer is often confirmed by measuring 0V at the secondary terminals (R and C on the control board) with a multimeter while line voltage is confirmed at the primary.

• Specs: 40VA rated | Primary: 120V AC | Secondary: 24V AC | OEM part number HT01CN241 | Factory-matched output for Carrier low-voltage control circuits
• OEM vs Generic: This is a genuine OEM Carrier transformer manufactured to exact VA and voltage tolerances. Generic transformers with loose VA ratings can under-power control boards, causing nuisance lockouts, intermittent thermostat dropouts, and premature board failure — costing far more than the part itself.
• Install difficulty: 2/5 — Shut off power at the breaker and verify zero voltage before disconnecting. Tools needed: flathead and Phillips screwdrivers, multimeter, wire nuts or quick-connect terminals. Photograph all wiring connections before removing the old transformer. Primary wires carry 120V — treat with appropriate care.
• Warranty: 1-year OEM factory warranty against defects. In-stock units ship same business day when ordered before cutoff.

Compatibility: Engineered as a direct OEM replacement for the Carrier FB4CNFS24L00ADAA fan coil air handler. Verify your existing transformer's VA rating and primary/secondary voltages on the unit data plate or component label before ordering. Our HVAC parts specialists are available to confirm fitment — order with confidence.