I am a new owner of 2007 fun finder. It is the 18 ft model. I am have trouble understanding the water system. When I hook up to city water I have a drain from the bottom of the trailer (on the left side as you are facing the trailer) that water pours out. I have looked under the bed and see three red valves. One looks like it shuts off the water to the hot water tank. Another appears to shut the hot water off from the hot water tank and I am assuming the other is a master valve.
Those valves (3 of them) are your water heater by-pass valves. You don't want to fill your water heater with anti-freeze and those are used to take the tank "out of the loop" so that you can fill the "hot" lines with anti-freeze. There is/are some other threads on this forum that describe how they are used.
There is a small valve down at the base of the storage tank that does not appear to do anything. Nonetheless, I can't stop the water from pouring out the bottow.
The freshwater tank drain is a "rotating petcock" style valve...it will spin all the way around. It is a handle connected to a rod with a hole in it. If the handle is perpendicular to the hose/pipe, the valve is closed, if the handle is aligned parallel or with the pipe, the valve is open. That is the common relationship with most of the valves you'll find on the trailer; if the handle cuts across the pipe, the valve is closed (think a dam across the pipe) and if the handle is aligned with the pipe, the valve is open (think the water will follow the handle). If the handle is perpendicular to the pipe and you still have water flowing out of it, the valve is probably faulty. Not likely...they are fairly "bullet proof".
The drain lines that are open appear to exit the trailer on the left side (as your facing the trailer) of the water tank.
Those two pipes are the "low point" drains. They are used in conjunction with the 3 valves at the water heater lines to drain the water out of the trailer in preparation for winterization. On most FunFinders, those valves are spring loaded plunger types with a metal ring (like a small key ring) in a post that you pull up to open and then push the post back down to close. There will be two pipes; one for the hot and one for the cold lines. If you have water coming out of one of them, then the valve is open. You need to find the little key rings and make sure the posts are pushed back in. If I understand your problem, this is where the water is coming out...it would indicate that whoever winterized or drained the anti-freeze out of the trailer left those valves open.
What am I missing? In addition, there appears to be two pipes exiting from the hot water heater on the outside. Should there be pipe plugs in those pipes or outlets.
No plugs...see above 
The pipes just hang down and provide the outlet for the low point valves that are located in the "T" fitting above them. The location for those valves varies based on the model and make of trailer, but, on most FunFinders, they are located near the water heater and may be behind or under another panel in that area.
I have got a thousand questions, but that is enough for now.
Thanks
Razorbak
