OEM Carrier 40VA Control Transformer HT01CN236 for Model FA4ANF018005AFAA

This OEM control transformer (part# HT01CN236) is the factory-specified replacement for the Carrier FA4ANF018005AFAA fan coil air handler. The transformer steps down 120V line voltage to 24V AC, powering the entire low-voltage control circuit — including the thermostat, contactor coil, and any connected zone controls. When this transformer fails, nothing in the system responds: the thermostat goes dark, the air handler ignores all calls for cooling or heating, and the unit sits completely silent. A failed transformer is often mistaken for a bad thermostat or control board, so always verify 24V output at the secondary terminals before replacing costlier components.

• Specs: 40VA rating | Primary: 120V AC | Secondary: 24V AC | OEM part number HT01CN236 | Factory-matched output tolerance for reliable low-voltage control
• OEM vs Generic: This OEM transformer is wound to Carrier's exact VA rating and insulation class. Generic alternatives frequently run under-rated VA, causing the transformer to overheat and trip its internal fuse under normal system load — especially with added accessories like humidistats or zone boards.
• Install difficulty: 2/5 — Disconnect power at the breaker and verify voltage is absent before proceeding. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter. Label all low-voltage wires before removing the old transformer. Confirm 24V output at secondary terminals after installation before closing the panel.
• Warranty: 1-year OEM factory warranty against defects. In-stock units ship the same business day from our warehouse.

Compatibility: Designed for the Carrier FA4ANF018005AFAA fan coil air handler. Always verify your existing transformer's primary voltage, secondary voltage, and VA rating against your unit's data plate before ordering. If your system includes accessories such as a humidifier, UV light, or zone controller drawing additional VA, confirm total load does not exceed 40VA. Our parts specialists are available to verify fitment before you order — reach out before purchasing if you have any questions.