OEM Carrier Transformer 40VA 120V to 24V for Model LC748LCCSRLYX2600

This OEM step-down transformer (part number HT01BD702) is the factory-specified replacement for the Carrier LC748LCCSRLYX2600. The transformer is the heart of the 24V control circuit, converting 120V line voltage down to the 24VAC signal that powers your thermostat, contactor coil, gas valve, and control board relay logic. When the transformer fails, the entire low-voltage control circuit goes dead — the thermostat goes blank, the system refuses to respond to any call for heating or cooling, and a multimeter across the secondary terminals reads zero volts. A blown transformer is often the result of a short somewhere downstream in the 24V circuit, so inspect the control wiring and components before installing the replacement.

• Specs: 40VA rated | Primary: 120VAC | Secondary: 24VAC | OEM part number HT01BD702 | Factory-matched output tolerance for reliable control circuit operation
• OEM vs Generic: This is the factory OEM unit — wound to exact VA and voltage specifications for the LC748LCCSRLYX2600 control board. Generic transformers may run under-rated VA, causing overheating, nuisance trips, or premature failure under full control-circuit load.
• Install difficulty: 2/5 — Disconnect power at the breaker and verify zero voltage before handling. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter. Photograph all wiring connections before removal. Check secondary fuse and downstream wiring for shorts before energizing the new transformer.
• Warranty: 1-year OEM factory warranty against defects. Ships same business day from our warehouse when ordered before 3 PM local time.

Compatibility: Designed for the Carrier model LC748LCCSRLYX2600. Verify your existing transformer's primary voltage (120V), secondary voltage (24V), and VA rating on the unit data plate or existing component label before ordering. Need help confirming fitment? Our HVAC parts specialists verify compatibility before your order ships.