Originally Posted by spikesnet
I'm going to put everything back together and wait till tomorrow when you guys are back on and can let me know about this drain valve, rather then make a messy mistake.
I unfortunately do not have a good answer for you about the valves. Other than to say, they are cheap and I don't understand why they are used when you can buy a really nice brass ball valve for $6.
You mentioned draining to the back yard, keep in mind that you are draining just using gravity, so it will not flow up hill. :-)
I agree the element is bad.
I am not sure what to say about the plastic valve issue, other than to say I think your correct that it is possible that it is could be unscrewing the valve. Although, my guess is that it is just a cheap valve and it is going to leak some when you open it. .. but please don't blame me if it pops out and dumps the water! My gas tank has a normal looking bib valve and it still leaks some water when you drain it with a hose on it, but it is not a ton of water, but some does leak out onto the floor.
If it were me, I would do my best to setup some type of alternate drainage / clean up plan in case that thing pops out. (make sure the water has cooled down first). I would have what ever I could ready to hold the water if necessary, and have tarps down on the floor. Have a kiddie pool cut away that you can wedge under the valve if necessary, 5 gallon pails, etc. Just in case... Having all of your bath towels ready can help alot also. A big bath towel can help contain a gallon + of water...
I am not sure a plumber would really have any other way to deal with this other than to say that they likely have an E&O insurance policy that would cover the water damage they did to your home if this valve dumps all the water at once.
Good luck, hopefully someone else will have some other ideas.