OEM Carrier 40VA Control Transformer HT01BD236 for Model C4850C50ZG035600

This is the OEM factory-specified control transformer (part# HT01BD236) for the Carrier C4850C50ZG035600 packaged rooftop unit. The transformer steps down line voltage (120V) to the 24V signal voltage that powers your thermostat, control board, contactor coil, and all low-voltage safety circuits. When this transformer fails, the entire control circuit goes dead — the thermostat becomes unresponsive, the system won't call for heating or cooling, and no fault codes will display because the board itself has no power. Replacing this part with a genuine OEM unit restores full factory-spec performance and protects downstream components from voltage irregularities caused by undersized or out-of-tolerance aftermarket substitutes.

• Specs: 40VA rating | Primary: 120V | Secondary: 24V | OEM part number HT01BD236 | Factory-matched impedance and core rating for Carrier C4850C50ZG035600
• OEM vs Generic: OEM transformers are wound to exact VA and voltage tolerances. Undersized generic transformers can sag under load, causing erratic thermostat behavior, nuisance lockouts, or premature contactor coil failure — making the OEM part the clear long-term value.
• Install difficulty: 2/5 — Disconnect all power before beginning. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter, and wire nuts or spade terminals. Verify incoming voltage is within spec before installing. Always photograph or label existing wiring connections before removal.
• Warranty: 1-year OEM factory warranty against defects in materials and workmanship. In-stock and ships same business day from our warehouse.

Compatibility: Designed specifically for the Carrier C4850C50ZG035600 packaged rooftop unit. Confirm the 40VA, 120V primary / 24V secondary specification against your unit's data plate and wiring diagram before ordering. Our HVAC parts specialists are available to verify fitment — order with confidence and get back up and running today.