Thanks Weedmeister. Hmmmm, this brings up another issue I briefly read about on another thread. I don't know anything about this and would have never thought of it on my own. If we turn off the water supply, flip the breaker on the hot water heater and don't drain it, will the water be skunky monkey when we return a couple months later? Or, when we fire it up upon returning will that kill the bugs? After all, this does supply our kitchen. Draining it is not gonna happen, and I am probably making a mountain out of a mole hill here, but just thinking out loud. I wish my heater was on an outside wall. That would help. No such luck. The original floor plans called for this water heater to be installed in the attic. Our builders told us how much more trouble and expense it would be to install it that way. They convinced us to put it in this pantry closet. I don't think the attic would have been any better.....maybe in some ways even worse. Every replacement would have meant dragging a water heater up one of those pull down attic stair deals. Yikes! Makes my back hurt just thinking about it. Thank you.....thank you all.

They are thermostatically controlled. The tank should still have water but at a less than full level. Next time turn the WH control to pilot.

Tightening the stem packing nut or adding additional stem packing material will have absolutely no effect on stopping a leak where the water is leaking through the valve. The stem packing is solely to prevent water from leaking around the stem shaft. To answer the original question, "Is there a packing washer inside the valve?", the answer is "Maybe, but it is more likely that the valve is just a cast plastic body with a plastic internal seat and the stem is a one piece plastic casting including the washer face. Back in the early 80's some engineering genius sold the water heater industry a load of baloney about how much heat energy was being radiated through a metal valve and encouraged the use of the plastic valves as an energy conservation measure. Of course the water heater manufacturers liked the idea because the plastic valves are about $2 cheaper than a brass valve, and when you are making a million units a year, saving $2 a unit adds up to a substantial savings. On the other hand, out here in the real world it has been shown time and time again that the first time that valve is opened it is anybodies guess if it will ever close properly again. The simple solution is to drain the water heater and remove the plastic valve then replace it with a brass "3/4" Boiler stop cock valve". Some of the high efficiency water heaters have a thicker insulation blanket so it is sometimes difficult to install a common boiler cock valve. In this case there are two solutions. 1.You can install a short 3/4" pipe nipple into the tank, then install a female "boiler cock valve" of they also make a "long shank boiler cock" that has a longer male pipe end on the input side of the valve. The replacement valves can be purchased at any local hardware or home supply store for about $8 to $10. You will also need either some pipe dope or Yellow Triple Density PTFE (Teflon) tape" to put on the threads before installing the valve.

What is all the hot water needed for? A gas heater doesn't have to be in a well ventilated space because waste gases must be vented to the outdoors. It just needs source air and that's very easily done. Running a gas line is never a structural issue...it's a money issue. If two 50 gal units is a small fortune to operate...wouldn't one be 1/2 a small fortune? Still sound like a lot. I mean it's not like the second unit would cost 2x,4x,10x more than the first unit. That is kind of the deal if you want lots and lots of hot water on demand...it costs money. Solar can get you lots of pretty cheap hot water, at least DIY. The units you buy seem kind of expensive to me for what they are.