OEM Carrier 40VA Control Transformer for Model C48A402764

This is the factory OEM replacement control transformer (part number HT01BD702) for the Carrier C48A402764 packaged unit. The transformer steps line voltage (120V) down to the 24V required by your thermostat, control board, contactor coil, and all other low-voltage control circuit components. When this transformer fails, the entire control circuit goes dead — the thermostat goes blank, the system won't respond to any commands, and nothing operates. It is often the first component to check when a unit shows absolutely no sign of life despite confirmed line voltage at the unit.

• Specs: 40VA rated | 120V primary / 24V secondary | OEM part number HT01BD702 | Factory-matched output for Carrier C48A402764 control circuit requirements
• OEM vs Generic: OEM transformers are wound to exact VA and voltage tolerances required by the factory control board. Undersized or off-tolerance generic transformers can overload, trip internal thermal protection repeatedly, or fail to hold 24V under full control circuit load — leading to erratic system behavior and callbacks.
• Install difficulty: 2/5 — Always disconnect power at the disconnect box and confirm voltage is absent with a multimeter before beginning. Tools needed: flathead and Phillips screwdrivers, wire nuts or spade terminals, multimeter. Note wire colors and terminal positions before removing the old transformer.
• Warranty: 1-year OEM factory warranty against defects. In-stock and ships same business day from our warehouse.

Compatibility: Designed specifically for the Carrier C48A402764 packaged unit. Verify your existing transformer's VA rating and primary/secondary voltages on the data plate before ordering. If your system is tripping the transformer repeatedly, inspect the 24V circuit for shorts before installing a new unit. Need help confirming fitment? Our HVAC parts team verifies compatibility before you order — contact us today and get your system back online fast.