Some water vapor is normal, you say spraying water though. Im sure
Carrier can tell you how much is normal, an improperly angled exhaust
is possible as is maybe [ Im guessing ] improper furnace angle for
draining. My PVC exhaust does not freeze at - 20f and properly
instaled they should rarely freeze. Im sure they are used where it gets
to -60F. Water vapor is normal as 93% of the heat is removed and NG
contains allot of water. That is why you cannot vent HE furnaces
through an unlined chimney, water and acid will eat brick. If you
really drip water it may be of concern. Check the level of the exhaust
and call Carrier to see what they recommend and how to check things
out. Your furnace drains water from combustion, check that also.