OEM Carrier Control Transformer 40VA 120V/24V for Model LC748LCCSRLY2601

This OEM Carrier transformer (part number HT01BD702) is the factory-specified replacement for the LC748LCCSRLY2601 system. The transformer steps down 120V line voltage to the 24V AC signal required to power your thermostat, control board, and all low-voltage control circuits. When this part fails, the entire control circuit goes dark — your thermostat loses power, the system becomes completely unresponsive, and no heating or cooling function can be initiated. A failed transformer is often mistaken for a bad thermostat or control board, making it the first part technicians check when nothing works.

• Specs: 120V primary input | 24V secondary output | 40VA rating | Factory-matched OEM tolerances | UL listed
• OEM vs Generic: OEM transformers like this HT01BD702 are wound to exact factory VA and voltage specifications. Generic units frequently deliver unstable output voltage, which can damage sensitive control boards and void system warranties — not a risk worth taking on the most critical low-voltage component in the system.
• Install difficulty: 2/5 — Shut off all power to the unit at the breaker before beginning. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter. Photograph all wiring connections before disconnecting. Verify 24V output with a multimeter after installation before restoring full power.
• Warranty: 1-year OEM factory warranty on part HT01BD702. In-stock and ships same business day from our NationalHVACParts.com warehouse.

Compatibility: Designed as a direct OEM replacement for Carrier model LC748LCCSRLY2601. Always verify your existing transformer's primary voltage, secondary voltage, and VA rating on the original part's label before ordering. Our fitment team is available to confirm compatibility before you purchase — same-day shipping available on all in-stock orders.