OEM Carrier 40VA Control Transformer for Model C4850C50Z3035600

This OEM replacement transformer (part# HT01BD236) is the factory-specified step-down transformer for the Carrier C4850C50Z3035600 packaged unit. It converts 120V primary power to the 24V AC signal that powers your thermostat, control board, contactor coil, and all low-voltage safety circuits. When this transformer fails, the entire control circuit goes dark — the thermostat becomes unresponsive, the system will not call for heating or cooling, and no diagnostic fault codes will appear because the board itself has no power.

• Specs: 40VA rating | 120V primary / 24V secondary | Class 2 output | Factory-matched for Carrier C4850C50Z3035600 packaged unit control circuit
• OEM vs Generic: This OEM unit is wound and potted to Carrier's exact VA and thermal specifications. Undersized or off-tolerance generic transformers frequently overheat under full 24V circuit load, causing repeated nuisance failures and potential damage to downstream control boards.
• Install difficulty: 2/5 — Disconnect power at the disconnect box and verify zero voltage with a multimeter before beginning. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter, wire nuts or spade terminals. Label all low-voltage wires before removal. Reinstallation is straightforward with direct wire-for-wire replacement.
• Warranty: 1-year OEM factory warranty against defects in materials and workmanship. Ships same business day from our stocked warehouse.

Compatibility: Designed for the Carrier C4850C50Z3035600 packaged unit. Always verify your existing transformer's VA rating and primary/secondary voltages on the unit data plate or wiring diagram before ordering. Need fitment confirmation? Our HVAC parts specialists verify compatibility before your order ships — no guesswork required.