OEM Carrier 40VA Control Transformer for Model C4850C48ZG105610

This is the factory-specified OEM replacement control transformer (part# HT01BD236) for the Carrier C4850C48ZG105610 packaged unit. The transformer steps down 120V line voltage to the 24V signal required by your thermostat, control board, contactor coil, and all low-voltage safety circuits. When the transformer fails — due to a shorted wire, failed component drawing excess current, or simple age — nothing in the system will respond: the thermostat goes blank, the contactor won't pull in, and the unit sits completely dead. Replacing the transformer is one of the most straightforward repairs in HVAC service.

• Specs: 40VA rating | Primary: 120V | Secondary: 24V | Class 2 output | Designed for Carrier packaged unit control circuits
• OEM vs Generic: The OEM HT01BD236 transformer is wound and rated to Carrier's exact specifications, ensuring proper VA headroom for all connected low-voltage loads. Generic substitutes are frequently undersized in practice, causing nuisance shutdowns and overheating when multiple control components draw simultaneously.
• Install difficulty: 2/5 — Disconnect power and verify voltage is off before beginning. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter. Before removing the old transformer, photograph or sketch the wiring connections on both primary and secondary terminals to ensure correct reinstallation.
• Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Engineered specifically for the Carrier C4850C48ZG105610 packaged unit. Verify your existing transformer's VA rating and primary/secondary voltages on the unit data plate or wiring diagram before ordering. If your system is tripping the transformer repeatedly, inspect all 24V wiring for shorts before installing the replacement. Have questions about fitment? Our HVAC parts specialists confirm compatibility before you order — just ask.