Water Heater Drain Pan Drain completely cloged

[Fried Chicken]

Replace that drain valve with a straight 3/4 ball valve so you can get access THROUGH the valve.
With both top shut offs closed and nothing else open to air water will come out of the heater so slowly you can do an element, drain valve or T&P valve replacement without draining the heater. ;^)
Milkstone remover found at the farm store is a VERY effective lime dissolver.

I'll do that tomorrow and check out Milkstone remover.
I have some phosphoric acid laying around for de-rusting tools, but I also have the 9% vinegar. I'm hesitant to use anything stronger as it might cause trouble with the lining in the water heater.

 

[Sidecarflip]

Most modern water heaters are 'glass' lined. You won't hurt it any more than the lime scale is...

 

[Fried Chicken]

Most modern water heaters are 'glass' lined. You won't hurt it any more than the lime scale is...

Interesting, I was wondering what they used for the liner. Regardless, there are still all the pipes valves and fittings. We'll see, I finally got the thing drained and tomorrow I can get a ball valve for it