OEM Carrier 40VA Control Transformer HT01BD236 for Model C50A202051

This OEM replacement transformer (part number HT01BD236) is the factory-specified control circuit transformer for the Carrier C50A202051 commercial packaged unit. The transformer steps down 120V line voltage to the 24V AC signal that powers your thermostat, contactor coil, control board, and all low-voltage safety circuits. When this component fails, the entire control system goes dark — the thermostat loses power, the unit stops responding to calls for heating or cooling, and nothing operates. If you measure 120V at primary terminals but zero volts at the secondary, this transformer is the likely culprit.

• Specs: 40VA rated | Primary: 120V AC | Secondary: 24V AC | OEM part number HT01BD236 | Direct factory replacement with matched mounting footprint
• OEM vs Generic: OEM transformers are wound to exact VA and voltage specifications, preventing under-voltage faults that cause nuisance lockouts. Generic units frequently run low on secondary output under full load, causing intermittent control board resets and contactor chatter.
• Install difficulty: 2/5 — Shut off all power at the disconnect before beginning. Tools needed: flathead and Phillips screwdrivers, multimeter, wire nuts or terminal connectors. Label all wires before disconnecting, verify 0V at primary terminals before touching wiring, and confirm secondary output reads 24–26V AC after installation before closing the panel.
• Warranty: 1-year OEM factory warranty against defects in materials and workmanship. Ships same business day from our climate-controlled parts warehouse.

Compatibility: Engineered specifically for the Carrier C50A202051 commercial rooftop/packaged unit. Always verify your existing transformer's VA rating and primary/secondary voltages on the data plate before ordering to ensure a drop-in fit. Our parts specialists are available to confirm compatibility before you purchase — same-day shipping available on all in-stock orders placed before 3 PM local time.