OEM Carrier Transformer 40VA 120V/24V for Model FF1DNA030011AAAA

This OEM step-down transformer (part number HT01CN236) is the factory-specified replacement for the Carrier FF1DNA030011AAAA air handler. The transformer converts 120V line voltage to the 24V AC signal that powers your thermostat, control board, and all low-voltage control circuit components. When this part fails, the entire control circuit goes dead — the thermostat display may go blank, and the system will not respond to any heating or cooling calls. It is often the first component to inspect when nothing works and the unit is otherwise receiving power.

• Specs: 40VA rating | 120V primary / 24V secondary | Class 2 transformer | OEM part number HT01CN236 | Direct factory replacement
• OEM vs Generic: This OEM transformer is wound to Carrier's exact VA and voltage tolerance specifications. Generic replacements may underperform under full control-circuit load, causing nuisance lockouts, erratic thermostat behavior, or premature failure of downstream components.
• Install difficulty: 2/5 — Disconnect power at the breaker before servicing. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter. Verify 120V primary input and 24V secondary output with a multimeter before and after installation. Always label or photograph existing wiring before removal.
• Warranty: 1-year OEM factory warranty against defects. Orders placed by cutoff ship same business day from our warehouse.

Compatibility: Designed specifically for the Carrier FF1DNA030011AAAA air handler. Verify transformer VA rating and primary/secondary voltage on your unit's data plate or wiring diagram before ordering. Have questions about fitment? Our HVAC parts specialists confirm compatibility before your order ships — no guesswork required.