OEM Carrier Control Transformer 40VA for Model C4850C50AJ04161

This OEM replacement transformer (part number HT01BD236) is the factory-specified control transformer for the Carrier C4850C50AJ04161 packaged unit. The transformer steps down line voltage (120V) to the 24V AC signal required by your thermostat, control board, contactor coil, and all low-voltage safety circuits. When the transformer fails, the entire control circuit goes dead — your thermostat loses power, the system won't respond to any call for heating or cooling, and you may blow a low-voltage fuse repeatedly. This is a very common failure point after electrical surges or a shorted low-voltage wire.

• Specs: 40VA rated | 120V primary / 24V secondary | Foot-mount design | OEM part number HT01BD236 | Factory-matched output tolerance for reliable low-voltage circuit operation
• OEM vs Generic: OEM transformers from Carrier maintain precise voltage output under load. Generic units often sag below 24V under full circuit demand, causing erratic contactor chatter, nuisance lockouts, and premature control board failure.
• Install difficulty: 2/5 — Shut off all power at the disconnect and breaker before servicing. Tools needed: flathead and Phillips screwdrivers, multimeter, wire nuts or spade connectors. Confirm secondary output reads 24–28V AC before reconnecting load wiring. Photograph all wiring connections before disconnecting.
• Warranty: 1-year OEM factory warranty. Order by 3 PM local time and ships same business day from our climate-controlled warehouse.

Compatibility: Engineered specifically for the Carrier C4850C50AJ04161 packaged unit. Always verify the VA rating and primary/secondary voltages printed on your existing transformer's label before ordering — some configurations may use a different VA rating. Our fitment team is available to confirm compatibility before you purchase. In stock and ships today — don't leave your system down overnight.