OEM Carrier 40VA Control Transformer for Model FX4DNF019T05AAAA — Part# HT01CN241

This is the factory OEM replacement control transformer (part# HT01CN241) for the Carrier FX4DNF019T05AAAA fan coil air handler. The transformer steps down line voltage (120V) to the 24V AC signal that powers the entire low-voltage control circuit — thermostat, control board, contactor coil, and zone valves. When this component fails, the result is complete loss of thermostat response, a blank display, or a system that simply won't respond to any commands. It is often the first component to inspect when nothing works and the disconnect has power.

• Specs: 40VA rating | 120V primary input | 24V secondary output | Factory OEM part number HT01CN241 | Engineered to Carrier's original wiring harness and mounting configuration
• OEM vs Generic: OEM transformers like this HT01CN241 are wound to exact VA and voltage tolerances required by Carrier's control board. Undersized or off-spec generic units can brown out the control circuit, cause intermittent lockouts, or fail prematurely under full load conditions.
• Install difficulty: 2/5 — Disconnect power at the breaker and air handler disconnect before beginning. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter. Confirm 0V at transformer terminals before handling. Label all low-voltage wires before removal.
• Warranty: 1-year OEM factory warranty against defects. In-stock and ships same business day from our warehouse.

Compatibility: Designed as a direct OEM replacement for the Carrier FX4DNF019T05AAAA fan coil air handler. Always verify primary voltage on your unit's data plate matches 120V before ordering. If you are unsure of fitment, our parts specialists can confirm compatibility before you purchase — same-day shipping available on all in-stock orders.