OEM Carrier Transformer 40VA 120V to 24V for Model C48A402064

This is the genuine OEM replacement transformer (part number HT01BD702) for the Carrier C48A402064 packaged unit. The transformer steps down 120V line voltage to the 24V signal required by your thermostat, contactor coil, and all low-voltage control components. When this part fails, the entire control circuit goes dead — the thermostat goes blank, the contactor won't pull in, and neither heating nor cooling will operate. If your system is completely unresponsive despite confirmed power at the disconnect, a failed transformer is one of the first components to test.

• Specs: 40VA rating | 120V primary / 24V secondary | Factory-matched OEM part number HT01BD702 | Replaces failed or shorted transformers in Carrier C48A402064 packaged units
• OEM vs Generic: This factory OEM unit is wound to exact VA and voltage tolerances for the C48A402064 control circuit. Generic transformers may underperform under full load, causing nuisance tripping of the integrated thermal overload and erratic thermostat behavior.
• Install difficulty: 2/5 — Shut off all power at the unit disconnect before beginning. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter. Label or photograph all low-voltage wire connections before removing the old transformer. Verify 24V output at secondary terminals before reassembling.
• Warranty: 1-year OEM factory warranty. In-stock and ships same business day from our warehouse.

Compatibility: Designed for the Carrier C48A402064 packaged unit. Always verify your existing transformer's VA rating and primary/secondary voltages on the unit data plate or wiring diagram before ordering. Our fitment team is available to confirm compatibility prior to purchase — same-day shipping on all in-stock OEM parts.