My firend just bought a older home and wanted his bathroom redone. After gutting the bath, removing the old shower valves, replacing it with a Price Pfister single valve I noticed when checking for leaks that when I turned on the shut off valves to the shower that the entire house lost it's hot water. Thinking I had a bad valve, I went to Home Depot, returned it and reinstalled it. After a few days of construction, I wanted to test it before installing the backer board. To my surprise, I still have the same problem. When I turn on the shut off valves to the shower, the hot water in the house gets cold. Any suggestions?:confused:

Any chance this is an electric hot water heater?

Yes, it is electric

Well a couple of things could have happened. When you shut off the water to do the plumbing, you may have drained the water heater down enough to allow the element(s) to be out of the water. If they were powered at the time... they would burn out as soon as they were out of the water. There is a reset button on one or both of the elements... check that.

I have plenty off hot water. The only time I don't have hot water is when I open the shut off valves to the new shower

Do you mean you don't have ANY hot water in ENTIRE house when you open the new shower faucet ?

This I got to see. Please post picture of you plumbing.

I want to thank everyone for their comments. I finally figured out what was wrong. I seemed to me that it had to be in the new shower valve somewhere because if I isolated the valve via the Hot/Cold shut offs I would have hot water everywhere.

So this morning, I uncapped the shower nipple, put a 5 gallon bucket under it and opened up the shutt offs. It was then I discovered that I couldn't turn the water off with the shower handle. So I quickly closed the shut offs and tore apart the new valve. What I found was that the cold water side of the cylinder was stuck shut. Hence the cold water was running right on past the valve and into the hot water feed.

Once I exchanged the fixture, everything worked like a charm...

Thanks again for all of your help... This is a great help site.

Gary