OEM Carrier 40VA Control Transformer 208/230V–24V for Model PF4MNB043L00ABAA

This is the genuine OEM Carrier replacement transformer (part #HT01CN241) for the PF4MNB043L00ABAA fan coil and air handler unit. The transformer steps down the 208/230V line voltage to the 24V AC signal that powers your system's entire control circuit — including the thermostat, zone valves, contactor coil, and control board. When this part fails, the result is typically a completely unresponsive system: the thermostat goes blank, the unit won't call for heating or cooling, and no fault codes appear because the control circuit itself has no power. A blown fuse on the secondary side is the first symptom; a shorted transformer is the cause.

• Specs: 208/230V Primary | 24V Secondary | 40VA Rating | Direct OEM factory-matched replacement for part #HT01CN241
• OEM vs Generic: This is a genuine Carrier Factory Authorized Part, manufactured to exact voltage and VA tolerances. Generic transformers often run outside rated VA capacity, risking nuisance fuse blows and premature control board failure.
• Install Difficulty: 2/5 — Shut off power at the disconnect and breaker before starting. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter (to verify 24V output post-install). Photograph all wiring connections before disconnecting the old transformer. Replace the 3A secondary fuse if blown.
• Warranty: 1-year OEM manufacturer's warranty. In-stock orders ship same business day from our warehouse when placed before cutoff.

Compatibility: Designed as the direct OEM replacement for Carrier model PF4MNB043L00ABAA fan coil units. Verify your unit's data plate shows 208/230V primary input and 24V control circuit before ordering. Not sure if this is the right part? Contact our fitment team — we verify compatibility before you buy.