OEM Carrier Transformer 40VA 120V to 24V for Model FA4ANF030010AFAA

This is the factory-specified OEM replacement transformer (part number HT01CN236) for the Carrier FA4ANF030010AFAA air handler. The transformer is the backbone of your system's low-voltage control circuit — it steps incoming 120V line voltage down to 24V AC to power the thermostat, control board, and all relay coils. When the transformer fails, nothing in the system responds: the thermostat goes dark, contactors won't energize, and the unit sits completely dead despite power being present at the disconnect. A failed transformer is often caused by a shorted thermostat wire, a miswired control board, or simply age-related winding breakdown.

• Specs: Primary voltage: 120V AC | Secondary voltage: 24V AC | VA rating: 40VA | OEM part number: HT01CN236 | Factory-matched windings and mounting footprint
• OEM vs Generic: This OEM unit uses factory-wound copper coils with exact VA capacity for the FA4ANF030010AFAA control circuit. Generic transformers frequently underperform at rated VA, causing nuisance tripping or premature failure when multiple zone valves or accessories are on the circuit.
• Install difficulty: 2/5 — Disconnect all power before servicing. Tools needed: flathead and Phillips screwdrivers, multimeter, wire strippers. Before replacing, verify the transformer secondary reads 0V (not 24V) and check for a shorted thermostat wire that may have caused the original failure. Replace the 3A fuse on the control board if present.
• Warranty: 1-year OEM factory warranty against defects in materials and workmanship. Ships same business day from our warehouse when ordered before 3PM local time.

Compatibility: Engineered specifically for the Carrier FA4ANF030010AFAA air handler. Confirm your existing transformer's primary and secondary voltage ratings on the unit data plate before ordering. If you have added downstream accessories such as zone boards or humidifiers, verify total VA load does not exceed 40VA. Our HVAC parts specialists are available to confirm fitment before you order — zero guesswork, guaranteed.