Draining water heater problem

[Pirate]

Went to drain water heater, and nothing came out. Water supply off, relief valve open. 

Closed relief valve and shot some compressed air in drain valve. Nothing came out. Repeated it 4 times. Nada.

Shut relief valve and opened supply valve. Water came out drain valve. Good flow. not real dirty, but not clear.

Shut off supply valve, and opened relief valve. nothing coming out. ??? Repeated 3 times. No luck.
Any ideas?

[Pirate]

Tried the above a few more times and it drained a little and stopped. Blew more air in drain, and started flowing again. Fingers crossed. Glad I have a spare heater in the barn.

[Snipe Hunter]

..................Well water?

[meackerman]

last time I drained mine, I hooked up a 50' hose, gurgled a bit but nothing came out the hose.  hooked up a shorter hose and it drained.

[daddo]

Many years ago, I used to service and replace and clean water heaters. My method of draining them was to leave the water on and try the drain faucet first, working the open/close valve a few times might get it going. If not, my next procedure was to relieve all the pressure and close all valves and facets, then remove the drain valve quickly and place a short piece of pipe and ball valve in it's place. You have to have everything ready and work fast and have the shop vac going to pick up any water. The water might be hot, so if you can't handle hot water, don't do this.
After all of that, it still may not drain since the tank itself is just full of calcium (rocks and sludge). But turn the water back on anyway and open the new valve and see if it starts draining. If it does, I would turn off the water, disconnect both inlet and outlet pipes, cap off one side of the tank and connect the portable air compressor to the other side and use up to 60 psi to push all the water out.

When none of this would work, I got the dolley, grabbed onto the water heater and with the power of 20 gorillas, wrestle that dang thing out of there full.

I was much younger then.  

[Robert Adams]

Why did you turn off the water, open the relief valve and then open the drain. That does virtually nothing. Just put a hose on the drain and open it up and let the water fly. Put a stocking or sock or something over the end of the hose to see IF anything came out. 

    I have given up on trying to drain water heaters to get the gunk out. I have never had anything of and consequence come out of one. The stuff here just turns to concrete as soon as it hits the bottom of the tank. The only cleaning I have been able to do was to pull the bottom element and use a long chisel and hammer and bent rods to break up the crud a little then flush it out.

    If you want to eliminate the mineral buildup in your water heater get a water softener and forget about the drain. That said water softeners are very hard to install because you have no idea where the main water line is and then reroute it to somewhere you can put the water softener at etc. They can cost thousands to install here because we don't have basements.