OEM Carrier 40VA Control Transformer HT01CN241 for Model FB4BNF036005AAAA

This OEM replacement transformer (part number HT01CN241) is the factory-specified control circuit transformer for the Carrier FB4BNF036005AAAA fan coil air handler. Its sole but critical job is stepping line voltage (120V) down to the 24V signal voltage that powers your thermostat, contactor coil, and every low-voltage control on the system. When this transformer fails, absolutely nothing responds — the thermostat goes dark, the system refuses to start, and a multimeter will show zero volts on the secondary terminals. If your unit is completely dead and you've already ruled out a tripped breaker, this transformer is almost always the culprit.

• Specs: 40VA rated | Primary: 120V | Secondary: 24V | Factory-matched OEM part number HT01CN241 | Replaces original equipment exactly
• OEM vs Generic: OEM transformers from Carrier meet exact VA load ratings and insulation class requirements. Undersized or off-spec generic units can overheat, blow the internal fuse, or fail to hold voltage under full control circuit load — returning you to the same no-power symptom within weeks.
• Install difficulty: 2/5 — Shut off all power to the air handler before beginning. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter, needle-nose pliers. Note wire colors or photograph existing connections before disconnecting. The secondary fuse (typically 3A) should also be inspected and replaced if blown.
• Warranty: 1-year OEM factory warranty against defects. Orders placed before cutoff ship same business day from our stocked warehouse.

Compatibility: Engineered specifically for the Carrier FB4BNF036005AAAA fan coil air handler. Verify your existing transformer's primary/secondary voltage and VA rating on the data plate before ordering to confirm fitment. Our HVAC parts specialists are available to verify compatibility before you buy — call or chat today. In stock and ready to ship.