Draining water heater

[Lewis Davis]

I have a gas water heater and it is constantly draining water out of it. I can find no leak anywhere in the house or under the house but even when I turn the water supply valve off at the heater it will completely drain the water heater. Does anyone have any ideas

 

[Reach4]

At first I was thinking you needed a working thermal expansion tank. In that case, the water would come out of the temper and pressure relief valve. It would only take a little water each time, and the WH would not empty.

In your case, I think you are saying that if you turn off the water to water heater for 24 hours, then open a hot water faucet and open the drain valve on the WH, you only get drips of water. Is that right? Or if you get more, put a pan under that drain and say how much you get.

 

[Sponsor]

 

[Lewis Davis]

At first I was thinking you needed a working thermal expansion tank. In that case, the water would come out of the temper and pressure relief valve. It would only take a little water each time, and the WH would not empty.

In your case, I think you are saying that if you turn off the water to water heater for 24 hours, then open a hot water faucet and open the drain valve on the WH, you only get drips of water. Is that right? Or if you get more, put a pan under that drain and say how much you get.

Yes if I turn the water supply valve off at the tank when I come back and open the drain valve I get nothing out of it and I do get water out of the drain valve when the water is on so I know the drain valve is not plugged

 

[Reach4]

Yes if I turn the water supply valve off at the tank when I come back and open the drain valve I get nothing out of it

Open a hot water faucet when you open the drain valve, and see if that changes things.

Also, add a time factor into your description. Is 24 hours about right?

 

[Phog]

Lewis, when you open the drain valve & nothing comes out, do you have any hot water faucets open anywhere in the house? If not, try opening one up (with the cold supply to the heater still shut off) and see if that changes what happens when you open the drain valve.

It could just be a case of vacuum lock -- you have to allow a way for air to get back into the top of the tank to replace the water you're trying to drain out of the bottom. Or else the water won't flow out. Similar concept to how you can pick up liquid with a straw, by placing your finger over the top.

Finally, if this does end up being what is going on here, you should remember to *always* open up a hot faucet when you're trying to drain your tank. If not the vacuum you're creating can actually cause the tank to crumple inward & damage it.