OEM Carrier Control Transformer 40VA 120V/24V for Model LC750LCCMRAYX600

This OEM replacement transformer (part # HT01BD702) is the factory-specified step-down transformer for the Carrier LC750LCCMRAYX600 system. It converts 120V line voltage down to the 24V signal required to power the control board, thermostat, and low-voltage relay circuit. When this transformer fails, the entire control circuit goes dark — your thermostat will appear dead, contactors won't pull in, and the system will not respond to any call for heating or cooling. It is often the first component to check when nothing in the system responds but the unit has confirmed line voltage.

• Specs: 40VA rating | Primary: 120V AC | Secondary: 24V AC | OEM part number HT01BD702 | Compact chassis-mount design factory-matched to LC750LCCMRAYX600
• OEM vs Generic: The OEM HT01BD702 transformer meets exact VA and voltage tolerance specifications from Carrier. Generic substitutes frequently run outside rated VA capacity, causing overheating, nuisance tripping of internal fuses, and shortened service life for the control board.
• Install difficulty: 2/5 — Always disconnect power at the disconnect box before servicing. Tools needed: flathead and Phillips screwdrivers, multimeter (to verify 24V output after install), wire nuts or terminal screwdriver. Photograph or label all wiring connections before removing the old transformer.
• Warranty: 1-year OEM factory warranty. Orders placed before cutoff ship same business day from our warehouse.

Compatibility: Designed for the Carrier LC750LCCMRAYX600. Verify your existing transformer's VA rating and primary/secondary voltages on the data plate or wiring diagram inside the unit before ordering. If you are unsure of fitment, our HVAC parts team can confirm compatibility before you purchase — same-day shipping available on all stocked OEM components.