OEM Carrier 40VA Control Transformer HT01BD702 for Model C50A402064

This OEM replacement transformer (part# HT01BD702) is the factory-specified control circuit transformer for the Carrier C50A402064 commercial packaged unit. The transformer steps down 120V line voltage to the 24V signal voltage that powers your thermostat, contactor coil, and all low-voltage controls. When the transformer fails, the entire control circuit goes dead — the thermostat shows no response, the system won't energize, and no heating or cooling occurs. It is often the first component to check when a unit is completely unresponsive despite confirmed line power at the disconnect.

• Specs: 40VA rating | Primary: 120V | Secondary: 24V | OEM part number HT01BD702 | Factory-matched impedance and thermal protection
• OEM vs Generic: This OEM transformer is wound to Carrier's exact impedance and VA specifications, ensuring stable 24V output under full control circuit load. Generic transformers often run undervoltage under peak demand, causing nuisance lockouts and premature contactor coil failure.
• Install Difficulty: 2/5 — Disconnect all power before beginning. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter (to verify 24V output post-install). Label all low-voltage wires before disconnecting. The transformer typically mounts to the control panel bracket with two screws and uses push-on or screw-terminal connections.
• Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Engineered specifically for the Carrier C50A402064 commercial rooftop/packaged unit. Verify your unit's data plate shows 120V primary control voltage before ordering. If your unit uses a 208/240V primary, do not substitute — contact our team to confirm fitment. Our HVAC parts specialists are available to verify compatibility before you order, and we ship same day so your unit is back online fast.