Low Point drain on 2016 Flagstaff 831 BHDS

[Hef]

The other day is was at the storage checking on our camper and I decided to open both the hot and cold low point drains. I was surprised at the amount of water that drained out of the hot side. It probably drained for close to 5 minutes.

When you open the low point drains where exactly does the water come from? I am almost positive that I opened the low point drains before we left the campground last time and not very much water came out.

Thanks