OEM Carrier 40VA Control Transformer HT01BD702 for Model LC748LCCSRLYX2601

This OEM replacement control transformer (part number HT01BD702) is the factory-specified unit for the Carrier LC748LCCSRLYX2601 system. The transformer steps down line voltage from 120V to 24V AC, powering the low-voltage control circuit that allows your thermostat, contactor coil, gas valve, and control board to communicate and operate. When the transformer fails, the entire control circuit goes dark — the thermostat goes blank, the system produces no response to calls for heating or cooling, and nothing works. It is often the first component to check when a system appears completely dead with no obvious cause.

• Specs: 40VA rating | Primary: 120V AC | Secondary: 24V AC | OEM part number HT01BD702 | Factory-matched output for stable low-voltage control circuit operation
• OEM vs Generic: This OEM transformer is wound and rated to exact Carrier factory specifications, ensuring precise 24V output under full VA load. Generic transformers may under-deliver voltage under load, causing erratic thermostat behavior, nuisance lockouts, or premature contactor coil failure.
• Install difficulty: 2/5 — Shut off all power to the unit at the disconnect and breaker before beginning. Tools needed: flathead and Phillips screwdrivers, multimeter, wire stripper. Label or photograph all low-voltage wiring connections at the secondary terminals before disconnecting. Verify 24V output with a multimeter after installation before restoring full system operation.
• Warranty: 1-year OEM factory warranty included. In-stock and ships same business day from our warehouse.

Compatibility: Designed for the Carrier model LC748LCCSRLYX2601. Always verify your existing transformer's VA rating and primary/secondary voltage from 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 orders placed before 3PM local time.