OEM Carrier Transformer 40VA 120V–24V for Model C4850C50AK05161

This is the factory OEM replacement transformer (part number HT01BD236) for the Carrier C4850C50AK05161 packaged unit. The transformer is the heartbeat of your system's low-voltage control circuit — it steps 120V line voltage down to the 24V signal voltage that powers your thermostat, contactor coil, control board, and zone controls. When this transformer fails, absolutely nothing responds: the thermostat goes blank, the system won't call for heat or cooling, and no relays click. It's one of the first components to check when the entire control circuit goes silent.

• Specs: 40VA rating | 120V primary / 24V secondary | Ring-style chassis mount | OEM part number HT01BD236 | Factory-matched output tolerance for reliable low-voltage signaling
• OEM vs Generic: This OEM unit is wound and tested to Carrier's exact VA and voltage tolerances. Undersized or off-tolerance generic transformers can overheat, trip their internal breaker repeatedly, or fail to sustain voltage under full control-circuit load — leaving you chasing a misdiagnosis.
• Install difficulty: 2/5 — Disconnect all power before beginning. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter, wire nuts. Label all low-voltage wires before disconnecting the old unit. Confirm secondary output voltage with a multimeter before closing the panel.
• Warranty: 1-year OEM factory warranty against defects. Ships same business day from our climate-controlled warehouse.

Compatibility: Designed specifically for the Carrier C4850C50AK05161 packaged unit. Always verify the VA rating and primary/secondary voltages on your unit's data plate before ordering — installing an undersized transformer can cause nuisance tripping and premature failure. Have questions about fitment? Our HVAC parts specialists verify compatibility before you buy. Order now and ship today.