Water Heaters - Unable to drain water heater!

My water heater is leaking and I need to drain it while I wait for a technician. For some reason I cannot get it to drain.

Here's what I've done so far:
(1) Turn off the burner.
(2) Turn off the water inlet valve.
(3) Turn on hot water in a bathroom sink.
(4) Attached a garden hose to the water heater drain and open the drain.

A very small amount of water came out, then nothing. If I turn on the water inlet valve then water will come gushing out of the hose. But, as soon as I close that value...nothing. :wall:

Please help as I'd like to keep the water damage to a minumum. Thanks!

Open the hot water at the highest point above the WH. Or just open them all.
Also, the drain you mentioned..it is at the bottom of the tank..right? Not the one with a lever on it.

Yes, I have the hose attached to the drain at the bottom of the tank. My best guess the that drain valve has somehow gone bad and will only flow with high pressure.

It could become clogged with sediment...but if it cleared out with the water on, it should keep flowing. Try flushing it with the supply on for a few minutes..then see if you can get a gravity flow.

I did try flushing the system with the water on and the water that came out was clear. I will try this again for a bit longer and see if that helps. Thanks!

Oh, and the hose end needs to be lower than the drain. For instance, if the WH is in a basement, it won't drain uphill. I know that seems kinda elementary...but I've seen it before.

Lol. Yeah, that's not the problem. The heater is elevated in the garage and the end of the hose was on the driveway. Also, to further diagnose the problem I disconnected the hose and put a bowl under the drain. No water was coming out at all. /sigh

I have the same problem with my water heater. It is caused by the heat trap nipple in the hot water outlet acting as a check valve. Try lifting the test handle on the T&P valve to allow air into the tank.

I have the same problem with my water heater. It is caused by the heat trap nipple in the hot water outlet acting as a check valve. Try lifting the test handle on the T&P valve to allow air into the tank.

Shouldn't opening a hot water faucet in the house also let air into the system? Is it possible there is some sort of backflow prevention system which is not allowing the air to flow into the heater from the faucet?

Ack!! furd to the rescue again, and I almost mentioned that in my post. The heat trap he's talking about can act as a check valve and prevent flow back into the WH.

Just try lifting the T&P valve lever....

Thanks guys! I opened up the pressure release valve at the top and that allowed the tank to drain. :-)