OEM Carrier Transformer 40VA 120V to 24V for Model C4850C48ZN055600

This OEM replacement transformer (part number HT01BD236) is the factory-specified control circuit transformer for the Carrier C4850C48ZN055600 packaged unit. The transformer steps down line voltage from 120V to the 24V AC required by the thermostat, control board, contactor coil, and all low-voltage safety circuits. When the transformer fails, the entire control circuit goes dead — the thermostat shows no power, the system won't respond to calls for heating or cooling, and in some cases a tripped breaker or burnt smell may be present at the transformer terminals.

• Specs: Primary voltage: 120V AC | Secondary voltage: 24V AC | VA rating: 40VA | OEM part number: HT01BD236 | Factory-matched for Carrier packaged unit applications
• OEM vs Generic: The OEM HT01BD236 transformer is wound to exact Carrier factory specifications with proper VA rating and insulation class. Generic transformers often use undersized windings that overheat under full control circuit load, leading to repeat failures and potential damage to connected boards and contactors.
• Install difficulty: 2/5 — Shut off all power at the disconnect and breaker before beginning. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter. Always verify 0V at primary terminals before touching wiring. Label or photograph all low-voltage connections prior to removal.
• Warranty: 1-year OEM factory warranty against defects. Ships same business day from our NationalHVACParts.com warehouse when ordered before cutoff.

Compatibility: Designed for the Carrier C4850C48ZN055600 packaged unit. Verify your existing transformer's primary/secondary voltage and VA rating against your unit's data plate before ordering. If your transformer shows signs of burn marks, cracked insulation, or a blown internal fuse, do not simply replace the transformer without checking for a downstream short in the 24V control circuit — failure to do so may damage the new part. Our technical team is available to verify fitment and help diagnose root cause before you order.