OEM Carrier 40VA Control Transformer for Model C4850C50AJ04151

This OEM control transformer (part# HT01BD236) is the factory-specified replacement for the Carrier C4850C50AJ04151 packaged unit. The transformer steps down 120V line voltage to the 24V signal required by the thermostat, control board, contactor coil, and all low-voltage safety circuits. When this component fails, the entire control circuit goes dark — the thermostat shows no power, the system won't respond to any call for heating or cooling, and no fault codes will display because the board itself has lost its power supply.

• Specs: 40VA rating | Primary: 120V | Secondary: 24V | OEM part number HT01BD236 | Factory-matched for Carrier C4850C50AJ04151 packaged units
• OEM vs Generic: This OEM transformer is wound to exact factory VA and voltage specifications. Generic transformers frequently run under-rated VA, causing nuisance tripping of the internal thermal fuse under normal system load — especially in multi-stage or heat pump configurations where coil draw is higher.
• Install difficulty: 2/5 — Disconnect power at the disconnect box and confirm voltage is off with a multimeter before beginning. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, wire stripper, multimeter. Label all low-voltage wires before disconnecting from secondary terminals. Secure primary leads with appropriate wire nuts and confirm no exposed conductors before restoring power.
• Warranty: 1-year OEM factory warranty against defects. In-stock and ships same business day from our warehouse.

Compatibility: Designed and tested for the Carrier C4850C50AJ04151 packaged unit. Always verify your existing transformer's VA rating and primary/secondary voltages on the unit data plate before ordering to ensure a correct fit. Our parts specialists are available to confirm compatibility before you purchase — no guesswork required. Order today and receive same-day shipping on all in-stock OEM parts.