OEM Carrier 40VA Control Transformer HT01BD236 for Model C4850C50Z3055500

This is the factory OEM replacement transformer (part number HT01BD236) for the Carrier C4850C50Z3055500 packaged unit. The transformer steps down line voltage (120V) to the 24V AC signal that powers your thermostat, control board, contactor coil, and every other low-voltage control component in the system. When the transformer fails, the entire control circuit goes dead — the thermostat goes blank, the unit refuses to respond to any call for heating or cooling, and no fault codes appear because the board itself has lost power.

• Specs: 40VA rated | Primary: 120V AC | Secondary: 24V AC | OEM part number HT01BD236 | Factory-matched for Carrier packaged unit applications
• OEM vs Generic: OEM transformers are wound to exact VA and voltage tolerances required by the Carrier control board. Undersized or off-tolerance generic transformers can trip their internal thermal fuse prematurely or fail to sustain voltage under peak load, causing intermittent lockouts and nuisance shutdowns.
• Install difficulty: 2/5 — Disconnect all power before servicing. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter to verify 24V output after installation. Always label or photograph existing wiring before disconnecting the old transformer.
• Warranty: 1-year OEM factory warranty against defects. In stock and ships same business day from our warehouse.

Compatibility: Designed specifically for the Carrier C4850C50Z3055500 packaged unit. Verify your existing transformer's VA rating and primary/secondary voltages on the unit data plate or original component label before ordering. If your system has experienced a shorted control board or grounded low-voltage wiring, diagnose and correct the root cause before installing a new transformer to prevent repeat failure. Our HVAC parts specialists are available to confirm fitment — order with confidence and get same-day shipping.