OEM Carrier Control Transformer 40VA for Model C4850C48ZT075610

This OEM control transformer (part number HT01BD236) is the factory-specified replacement for the Carrier C4850C48ZT075610 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 the transformer fails, the entire control circuit loses power — the thermostat goes blank, the system won't respond to any calls for heating or cooling, and no relays or safety switches can operate. It is often the first component to inspect when nothing works at all.

• Specs: 40VA rated | Primary: 120V | Secondary: 24V | Class 2 control circuit transformer | Compact form factor for packaged unit installation
• OEM vs Generic: This OEM unit (HT01BD236) is wound to Carrier's exact VA rating and insulation class, ensuring the control board and contactor coil receive a stable, clean 24V signal. Undersized generic transformers can overheat under combined load, trip their internal fuse, or cause erratic low-voltage behavior across all connected components.
• Install difficulty: 2/5 — Shut off all power at the disconnect and breaker before servicing. Tools needed: flathead and Phillips screwdriver, multimeter (verify 0V before touching wires), wire nuts or spade connectors. Photograph all wiring connections before disconnecting the old unit. Verify primary and secondary voltages with a multimeter after installation before restoring full power.
• Warranty: 1-year OEM factory warranty. Orders placed before cutoff ship same business day from our climate-controlled warehouse.

Compatibility: Engineered specifically for the Carrier C4850C48ZT075610 packaged unit. Always confirm your existing transformer's VA rating and primary/secondary voltages on the unit's wiring diagram or data plate before ordering. Our fitment team is available to verify compatibility before you purchase — no guesswork required.