To start the crockpot carrots add the carrots into the crockpot and turn the crockpot on high or low.
Then in a bowl add the sugars, cinnamon and cornstarch. Add cold water and mix everything together then pour on top of the carrots. Allow the carrots to cook on high for 4 hours or low for 6. Be sure to stir the carrots at least twice that first hour to avoid settling of the cornstarch.
When the carrots are done, fold in the butter, then allow them to cool a bit and salt to taste.