Heater function and water drip
 

My wife was cold going to a car show this morning (60 in MN), so I turned the heater on. When I got out of the car, the AC water drip hose was dripping water. I thought that only dripped when AC was used. On way home I just left the top lever controls off, but left lower Inside control lever on, thinking that would not use the AC compressor. When, I got home it was dripping again.
This is an Old Air direct replacement AC kit, except using their Sanden compressor using the original inside controls. I don't have any history of how this normally functioned, since the car was apart when purchased. Is this supposed to drip and where does the water come from?
Sorry. I just realized maybe I should have put this below in heat and cool section.

The compressor also runs when it's above a certain temp and you select 'DE-ICE'
 

The design thinking is to remove the moisture from the air being blown across the windshield so it won't just fog up worse on a cool glass surface.

If you ran the defroster on the way to the show. or used a BI-LEVEL function where the air goes up and down, the compressor might have cycled.

The water dripping on the way home may have just been leftover water in the heater case.

Yes, according to the manual, the original set up says compressor runs on all functions except when lower control Vent is selected rather than Normal. I think the top levers automatically turn the compressor on unless you select Heat and the lower control Vent. All other top controls automatically force the lower control from Vent to Normal. So, that is my issue. When in Normal, it dries humid air for dry heat. Glad I figured that out. I don't have much time in this car driving with running the controls. It's usually off. Thanks.