OEM Carrier 40VA Control Transformer for Model C4850C50ZN040600 — Part HT01BD236

This OEM control transformer (part number HT01BD236) is the factory-specified replacement for the Carrier C4850C50ZN040600 packaged unit. The transformer steps down 120V line voltage to the 24V AC signal that powers your thermostat, control board, contactor coil, and all low-voltage safety circuits. When the transformer fails, the entire control circuit goes dead — the thermostat goes blank, the system won't respond to any call for heating or cooling, and no error codes are displayed because the board itself has lost power.

• Specs: 40VA rated | Primary: 120V AC | Secondary: 24V AC | OEM part number HT01BD236 | Factory-matched output tolerance for reliable low-voltage control circuit operation
• OEM vs Generic: This is a genuine OEM Carrier transformer wound to factory VA and voltage specifications. Generic transformers frequently run undersized, causing voltage sag under load that trips safety lockouts or burns contactor coils prematurely.
• Install Difficulty: 2/5 — Disconnect power at the breaker and verify with a non-contact voltage tester before touching any wiring. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter. Photograph all wiring connections before removal. Check and replace any blown 3A or 5A fuses on the control board at the same time.
• Warranty: 1-year OEM factory warranty against defects in materials and workmanship. Ships same business day from our climate-controlled warehouse.

Compatibility: Designed for the Carrier C4850C50ZN040600 packaged unit. Always verify your unit's data plate voltage requirements and existing transformer VA rating before ordering to ensure a correct fit. Not sure it's the right part? Our HVAC parts specialists confirm fitment before you buy — reach out before placing your order and we'll verify compatibility fast.