OEM Carrier 40VA Control Transformer for Model C4850C48ZG030200

This OEM control transformer (part# HT01BD236) is the factory-specified replacement for the Carrier C4850C48ZG030200 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 safety circuits. When this component fails, the entire control circuit goes dead — the thermostat loses power, the system stops responding to calls for heating or cooling, and no fault codes are generated because the board itself has no power to report them.

• Specs: 40VA rating | Primary: 120V | Secondary: 24V | Class 2 output | Compatible with single-stage and two-stage control circuits | Matches factory footprint and wire gauge for direct drop-in replacement
• OEM vs Generic: This OEM unit (HT01BD236) is wound to Carrier's exact VA tolerance, ensuring stable 24V output under full control-circuit load. Generic transformers frequently under-deliver VA capacity, causing nuisance lockouts and premature contactor coil burnout.
• Install difficulty: 2/5 — Disconnect power at the breaker and verify zero voltage with a multimeter before beginning. Tools needed: flathead and Phillips screwdrivers, multimeter, wire nuts or spade connectors. Label all low-voltage wiring before disconnecting. Confirm primary and secondary terminal polarity before restoring power.
• Warranty: 1-year OEM factory warranty. Orders placed by 3 PM ship same business day from our warehouse.

Compatibility: Engineered for the Carrier C4850C48ZG030200 packaged unit. Always verify your existing transformer's VA rating and primary/secondary voltages on the unit data plate before ordering — substituting an undersized VA transformer can damage connected components. Our fitment team is available to confirm compatibility before you buy.