OEM Carrier 40VA Control Transformer HT01BD236 for Model C50A402052

This OEM replacement transformer (part number HT01BD236) is the factory-specified step-down transformer for the Carrier C50A402052 commercial rooftop unit. The transformer converts 120V line voltage to the 24V AC signal that powers your control board, thermostat circuit, contactor coils, and all low-voltage components. When this transformer fails, the entire control circuit goes dead — the thermostat shows no response, the contactor won't energize, and the system refuses to start in any mode. A failed transformer is often misdiagnosed as a control board failure, making it a critical first diagnostic check.

• Specs: 40VA rated | 120V primary input | 24V secondary output | Factory-wound to OEM tolerances | Compatible with standard 24V HVAC control circuits
• OEM vs Generic: This is a genuine OEM Carrier transformer wound to exact factory VA and voltage specifications. Generic transformers frequently underperform under load, causing erratic contactor chatter, nuisance lockouts, and premature control board failures due to voltage sag.
• Install difficulty: 2/5 — Shut off all power at the disconnect before starting. Tools needed: flathead and Phillips screwdrivers, multimeter, wire nuts or spade connectors. Test secondary output (should read ~24–28V AC) before re-energizing the full system. Photograph all wiring connections before disconnecting.
• Warranty: 1-year OEM factory warranty against defects. Orders ship same business day from our stocked warehouse when placed before 3 PM local time.

Compatibility: Designed specifically for the Carrier C50A402052 commercial packaged rooftop unit. Verify your existing transformer's VA rating and primary/secondary voltages on the unit data plate or existing transformer label before ordering. Our fitment team is available to confirm compatibility prior to purchase — no guesswork required. In stock and ready to ship today.