OEM Carrier 40VA Control Transformer HT01BD236 for Model C4850C50ZG040500

This OEM control transformer (part number HT01BD236) is the factory-specified replacement for the Carrier C4850C50ZG040500 packaged unit. The transformer steps down 120V line voltage to the 24V signal required by your thermostat, control board, contactor coil, and all low-voltage control circuits. When it fails, absolutely nothing responds — the thermostat goes blank, the system won't call for heating or cooling, and no safety lockouts will trigger. If you've already verified your thermostat and control board are intact, a failed transformer is the next most likely culprit.

• Specs: 40VA rating | 120V primary / 24V secondary | Factory OEM part HT01BD236 | Direct drop-in replacement with matching mounting footprint and wire lead configuration
• OEM vs Generic: OEM transformers are wound to exact VA rating and insulation class for your unit. Undersized or off-brand transformers can overheat under peak load, blow fuses, or damage sensitive control boards — false economy on a part this critical.
• Install difficulty: 2/5 — Shut off all power to the unit at the disconnect before beginning. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter, wire nuts. Label or photograph all low-voltage wiring before disconnecting. Confirm 24V output with a multimeter after installation and before restoring full power.
• Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Engineered for the Carrier C4850C50ZG040500 packaged unit. Verify your existing transformer's VA rating and primary/secondary voltages on the data plate or original part before ordering. If you're unsure of fitment, our parts team confirms compatibility before you buy — no guesswork.