OEM Carrier 40VA Control Transformer for Model C48A302051

This OEM replacement transformer (part# HT01BD236) is the factory-specified control circuit transformer for the Carrier C48A302051 packaged unit. The transformer steps down 120V line voltage to the 24V low-voltage signal that powers your thermostat, contactor coil, and all control board logic. When the transformer fails — whether from a shorted wire, a blown fuse, or voltage spike — the entire control circuit goes dark: your thermostat goes blank, the system won't respond to any call for heating or cooling, and nothing operates.

• Specs: 40VA rating | Primary: 120V | Secondary: 24V | OEM part number HT01BD236 | Factory-matched impedance and thermal protection for the C48A302051 control circuit
• OEM vs Generic: OEM transformers are wound to exact VA and impedance tolerances required by the Carrier control board. Undersized or off-tolerance generic transformers can overheat, trip thermal cutoffs prematurely, or fail to sustain the 24V signal under full contactor load — leading to repeat failures.
• Install difficulty: 2/5 — Shut off all power at the disconnect and breaker before beginning. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter. Photograph all low-voltage wiring connections before disconnecting. Verify 24V output with a multimeter after installation before restoring full power.
• Warranty: 1-year OEM factory warranty. In-stock units ship same business day from our warehouse.

Compatibility: Designed for the Carrier C48A302051 packaged unit. Confirm your existing transformer's VA rating and primary/secondary voltages on the unit data plate before ordering. If your unit has a blown fuse on the secondary side, always identify and correct the root cause (shorted low-voltage wire or failed component) before installing the new transformer to prevent repeat failure. Our fitment team is available to verify compatibility before you order — ships same day.