OEM Carrier Control Transformer 40VA for Model C4850C48AY06051

This OEM replacement control transformer (part# HT01BD236) is the factory-specified unit for the Carrier C4850C48AY06051 packaged system. The transformer steps down line voltage from 120V to the 24V AC signal that powers your thermostat, contactor coil, and all low-voltage control circuits. When it fails, the entire control system goes dark — the thermostat loses power, the system stops responding to calls for heating or cooling, and you may blow a low-voltage fuse repeatedly. A failed transformer is one of the most common causes of a completely unresponsive HVAC system.

• Specs: 40VA rating | Primary: 120V | Secondary: 24V AC | Factory OEM part number HT01BD236 | Direct plug-and-play replacement for Carrier C4850C48AY06051
• OEM vs Generic: This factory OEM transformer is wound to exact VA and voltage specifications. Generic units often run under-rated VA capacity, causing them to overheat under full control-circuit load and fail prematurely — taking other components with them.
• Install difficulty: 2/5 — Shut off power at the breaker and disconnect the unit before beginning. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter, needle-nose pliers. Label and photograph all low-voltage wiring connections before removal. Verify 24V output at secondary terminals with a multimeter before reassembling.
• Warranty: 1-year OEM factory warranty. In-stock and ships same business day from our HVAC parts warehouse.

Compatibility: Designed specifically for the Carrier C4850C48AY06051 packaged unit. Always verify your existing transformer's VA rating and primary/secondary voltages on the unit data plate or wiring diagram before ordering. If you're unsure of fitment, our parts team is available to confirm compatibility before you purchase — we want to get it right the first time.