OEM Carrier Transformer 40VA 120V/24V for Model FB4CNP030T00AAAA

This OEM replacement transformer (part number HT01CN241) is the factory-specified control circuit transformer for the Carrier FB4CNP030T00AAAA fan coil air handler. The transformer steps down 120V line voltage to 24V to power the low-voltage control circuit — including the thermostat, control board, and all relay coils. When this transformer fails, the entire control circuit goes dark: the thermostat loses power, the system won't respond to calls for heating or cooling, and nothing runs. A failed transformer is often misdiagnosed as a bad control board, so always verify 24V output at the secondary terminals before replacing more expensive components.

• Specs: 40VA rating | 120V primary / 24V secondary | OEM part number HT01CN241 | Factory-matched form, fit, and function for the FB4CNP030T00AAAA air handler
• OEM vs Generic: OEM transformers are wound to exact VA and voltage tolerances, ensuring stable 24V output under full control circuit load. Undersized or off-tolerance generic units can sag under load, causing intermittent lockouts, nuisance tripping, or premature contactor failure.
• Install difficulty: 2/5 — Shut off all power at the disconnect and breaker before beginning. Tools needed: flathead and Phillips screwdrivers, multimeter, wire nuts or spade connectors. Photograph existing wiring before disconnecting. Verify 24V output at secondary after install before closing the panel.
• Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Designed specifically for the Carrier FB4CNP030T00AAAA fan coil air handler. Verify primary voltage (120V) and VA rating on your unit's data plate before ordering. If you're unsure of fitment, our HVAC parts team can confirm compatibility before you buy — same-day shipping on all in-stock orders.