OEM Carrier 40VA Control Transformer 120V/24V for Model PF4MNA025T00AAAA

This is the factory OEM replacement transformer (part number HT01CN241) for the Carrier PF4MNA025T00AAAA air handler. The transformer steps down 120V line voltage to the 24V signal used by the thermostat, control board, and all low-voltage control circuits. When this transformer fails, the entire control circuit goes dead — no thermostat response, no blower operation, and no heating or cooling, even though line power is present. A shorted low-voltage wiring harness is frequently the root cause of transformer failure, so inspect all 24V wiring before replacing the part.

• Specs: 120V primary / 24V secondary | 40VA output rating | Carrier OEM part number HT01CN241 | Factory-matched output tolerance for reliable control circuit operation
• OEM vs Generic: This OEM transformer is wound to Carrier's exact VA and voltage tolerances. Generic units often use undersized cores that overheat and fail prematurely — especially when connected to modern communicating thermostats that draw higher standby current.
• Install difficulty: 2/5 — Turn off all power at the breaker before beginning. Tools needed: flat-head and Phillips screwdrivers, multimeter, wire nuts. Verify 24V output at the secondary leads with a multimeter before reassembly. Always check low-voltage wiring for shorts prior to energizing the new transformer.
• Warranty: 1-year OEM factory warranty. Ships same business day from our warehouse.

Compatibility: Designed for the Carrier PF4MNA025T00AAAA air handler. Verify your existing transformer's VA rating and primary/secondary voltages on the unit's data plate before ordering. Our team is available to confirm fitment — reach out before you order if you have any questions.