OEM Carrier Transformer 40VA 120V to 24V for Model FV4CNB005L00ABAA

This OEM control circuit transformer (part# HT01CN236) is the factory-specified replacement for the Carrier FV4CNB005L00ABAA fan coil air handler. The transformer steps down 120V line voltage to the 24V signal used by the thermostat, control board, contactor, and all low-voltage safety controls. When it fails, absolutely nothing works — the thermostat goes dark, the system won't call for heating or cooling, and no fault codes appear because the control board itself is unpowered. A failed transformer is often mistaken for a bad thermostat or control board, so always verify 24V output at the secondary terminals before replacing other components.

• Specs: 40VA rated | Primary: 120V AC | Secondary: 24V AC | Class 2 control circuit transformer | Direct OEM replacement, part# HT01CN236
• OEM vs Generic: OEM transformers are wound to exact VA and voltage tolerances required by Carrier's control board. Undersized or off-tolerance generic units can trip thermal protection repeatedly, damaging downstream low-voltage components over time.
• Install difficulty: 2/5 — Disconnect power at the breaker and verify with a non-contact tester before touching any wiring. Tools needed: flathead and Phillips screwdrivers, multimeter, needle-nose pliers. Photograph all wiring connections before removal. Swap wire-for-wire on primary and secondary terminals.
• Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Engineered for the Carrier FV4CNB005L00ABAA fan coil air handler. Verify primary voltage (120V) and VA rating on your unit's data plate before ordering. Not sure it fits? Our HVAC parts specialists confirm fitment before every order — reach out before you buy.