OEM Carrier Control Transformer 40VA for Model C48A703064

This OEM replacement transformer (part# HT01BD702) is the factory-specified control circuit transformer for the Carrier C48A703064 packaged unit. It steps down 120V line voltage to the 24V signal required by your thermostat, contactor coil, gas valve, and control board. When this transformer fails, the entire control circuit goes dead — the thermostat loses power, nothing responds, and the system will not start at all. It is often the first component to check when a unit shows zero control-side activity.

• Specs: 40VA rating | Primary: 120V | Secondary: 24V | OEM part number HT01BD702 | Factory-matched output tolerance for stable low-voltage control circuit operation
• OEM vs Generic: This is a genuine Carrier OEM transformer engineered to exact VA and voltage specifications. Undersized or off-tolerance generic units can cause nuisance tripping, contactor chatter, and premature control board failure — OEM ensures a clean, stable 24V supply.
• Install difficulty: 2/5 — Disconnect all power before servicing. Tools needed: flathead and Phillips screwdrivers, multimeter, wire nuts or spade connectors. Verify secondary output (24V ±10%) with a multimeter before buttoning up the unit. Always label wires before disconnecting.
• Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Designed for the Carrier C48A703064 packaged unit. Verify your existing transformer's VA rating and primary/secondary voltages against your unit's data plate before ordering. If you're unsure about fitment, our HVAC parts specialists can confirm compatibility before you buy — same-day shipping available on all stocked OEM parts.