[chuckster57]

Look at the tube, if it has a threaded end it's a drain that needs a cap. If it is cut clean it is most likely an overflow.

You need to get underneath and inspect for drains and such so you KNOW what's what. Your looking for the following:

A single line, probably blue or white with a fitting for a cap.

A single line, probably white or blue with a clean cut end.

A PAIR of lines, with caps probably one red and one white or blue next to each other.

The single line with cap will be the fresh tank drain

The single line cut clean will be the overflow

The pair of lines will be the low point drains.

Let me know what you find, and we can go from there, but it sounds like the drain is open.