OEM Carrier 40VA Control Transformer for Model FA4ANF030008AFAA

This OEM Carrier control transformer (part# HT01CN236) is the factory-specified replacement for the FA4ANF030008AFAA air handler. The transformer steps down 120V line voltage to the 24V signal used by your thermostat, control board, and all low-voltage control components. When this part fails, the entire control circuit goes dead — your thermostat goes blank, the system won't respond to any calls for heating or cooling, and no diagnostic codes will display because the board itself has lost power.

• Specs: 40VA capacity | 120V primary / 24V secondary | Replaces OEM part# HT01CN236 | Factory-matched impedance and thermal protection
• OEM vs Generic: OEM transformers are wound to exact factory VA ratings and include built-in thermal cutoffs that protect downstream control boards from voltage surges. Generic replacements frequently run under-rated VA, causing overheating and premature control board failure — a far costlier repair.
• Install Difficulty: 2/5 — Shut off power at the breaker and verify zero voltage with a multimeter before touching any wiring. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter. Photograph all wire connections before disconnecting the old transformer. Label primary (120V) and secondary (24V) leads carefully.
• Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Direct OEM replacement for Carrier model FA4ANF030008AFAA air handler. Verify your existing transformer's VA rating and voltage specifications on the unit's data plate before ordering. If your system is blowing transformer fuses repeatedly, inspect downstream wiring for shorts before installing a new unit. Our fitment team is available to confirm compatibility before you order — contact us with your full model and serial number.