OEM Carrier 40VA Control Transformer for Model FX4DNF037010ABAA

This OEM control transformer (part# HT01CN241) is the factory-specified replacement for the Carrier FX4DNF037010ABAA air handler. The transformer steps down 120V line voltage to 24V AC, powering the low-voltage control circuit that connects your thermostat, contactor coil, and control board. When this component fails, the entire system goes dark — the thermostat loses power, the air handler won't respond to any call for heating or cooling, and no safety outputs will energize. It is often the first component to check when nothing works and the breaker is confirmed ON.

• Specs: 40VA rating | 120V primary → 24V secondary | Class 2 output | Compatible with standard residential control circuits | Replaces OEM part number HT01CN241
• OEM vs Generic: This OEM transformer is wound to Carrier's exact VA rating and insulation class. Generic transformers can be underrated for VA draw, causing overheating, nuisance tripping of the internal fuse, or premature failure when multiple accessories (humidifiers, zone boards, IAQ devices) share the circuit.
• Install difficulty: 2/5 — Disconnect power at the breaker before beginning. Tools needed: flathead and Phillips screwdrivers, wire nuts or quick-connect terminals, multimeter to confirm 24V output after installation. Photograph all wiring connections before removing the old transformer.
• Warranty: 1-year OEM factory warranty against defects. Orders placed before cutoff ship same business day from our climate-controlled warehouse.

Compatibility: Designed for the Carrier FX4DNF037010ABAA fan coil air handler. Always verify your existing transformer's VA rating and primary/secondary voltages on the data plate or wiring diagram before ordering — some air handlers with heavy accessory loads may require a higher VA-rated upgrade. Our HVAC parts specialists are available to confirm fitment before you purchase. In stock and ships today.