OEM Carrier 40VA Control Transformer HT01BD702 for Model LC748LCCSRMY2600

This OEM control circuit transformer (part number HT01BD702) is the factory-specified replacement for the Carrier LC748LCCSRMY2600. The transformer steps down 120V line voltage to the 24V signal voltage that powers your thermostat, control board, contactor coil, and all low-voltage safety circuits. When it fails, the entire control system goes dark — your thermostat goes blank, nothing responds, and the system will not attempt to heat or cool. A failed transformer is often misdiagnosed as a bad control board, making this an important first diagnostic step.

• Specs: 40VA rating | 120V primary / 24V secondary | Class 2 output | Factory-matched OEM design for Carrier LC748LCCSRMY2600 control circuitry
• OEM vs Generic: The OEM HT01BD702 transformer meets exact VA and voltage tolerance specifications. Generic replacements often carry looser tolerances that can under-power control boards or fail to hold coil voltage under load, leading to intermittent lockouts or nuisance faults.
• Install difficulty: 2/5 — Disconnect power at the breaker and verify with a multimeter before touching any wiring. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter. Always label or photograph all wire connections before removal.
• Warranty: 1-year OEM factory warranty. In-stock and ships same business day from our warehouse.

Compatibility: Designed as a direct OEM replacement for the Carrier LC748LCCSRMY2600. Verify your existing transformer's VA rating and primary/secondary voltage on the unit data plate or wiring diagram before ordering. If your secondary shows 0V with good line voltage present, the transformer is the likely fault. Our technical team is available to confirm fitment before you purchase — order with confidence and get back to comfort fast.