OEM Carrier Transformer 40VA 120V to 24V for Model C4850C50AK05061

This OEM control circuit transformer (part# HT01BD236) is the factory-specified replacement for the Carrier C4850C50AK05061 packaged unit. The transformer steps down 120V line voltage to the 24V signal required by the thermostat, control board, contactor coil, and all low-voltage safety circuits. When this transformer fails, the entire control circuit goes dead — the thermostat goes blank, the system won't respond to any call for heating or cooling, and no contactor or valve will actuate. It is one of the first components to check when nothing works at all.

• Specs: 40VA rating | Primary: 120V AC | Secondary: 24V AC | Class 2 control circuit transformer | Matches OEM HT01BD236 factory specification exactly
• OEM vs Generic: The OEM HT01BD236 transformer uses factory-wound coils rated to exact VA tolerance, ensuring stable 24V output under full load. Generic units often underperform at peak demand, causing nuisance lockouts and premature control board failure.
• Install difficulty: 2/5 — Shut off power at the disconnect and breaker before beginning. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter (to confirm 24V output after install). Label all wiring connections before disconnecting the old transformer.
• Warranty: 1-year OEM factory warranty. Orders placed before cutoff ship same business day from our stocked warehouse.

Compatibility: Designed for the Carrier C4850C50AK05061 packaged unit. Verify your existing transformer's VA rating and primary/secondary voltages on the unit data plate before ordering. If your control circuit is completely unresponsive and fuses have been ruled out, this transformer is the likely culprit. Our fitment team is available to confirm compatibility before you buy — in stock and ships today.