Just had our house re-plumbed, and now we have no hot water in the house. We've had the heater checked, and it seems to be fine, the pipes going from the heater into the house are hot to the touch, but all water coming out of the pipes in the house is cold( with flashes of hot when you first turn it on) water pressure with both hot and cold faucets are fine and strong, just no hot water. Is there a valve wrong? Crossed pipes?

Certainly would like to be helpful here. The most helpful thing anyone can say at this point is to say call the plumber back. It is his problem. Assuming of course that you hired someone to do the re-plumbing.
If you did the re-plumbing yourself post back with a description of what was done.

If you installed it yourself maybe you hooked the outlet line to the bottom of the heater.The water at the bottom tend's to remain cool and supplies only a small amount of heated water.(due to the fact that heat rises---therefore the hottest water and the largest amount of it will be coming out of the line at the top)

Had a friend do it. He has some plumbing experience, but he's stumped also. We simply copied the old lines, and replaced them with copper, so our only thought was it was the heater, but the heater people say it seems to be fine, based on all the tests. Heater has flame. Flame turns one bigger when we turn up the heat. Cold water pip in heater seems fine, hot water comes out of heater through heater drain, hot water pipe off heater into house is hot to the touch(oddly so if the main line into the house into the heater). We get full water flow if we turn on either hot or cold water taps in house, but both are cold. Don't see any crossed lines under the house. Hot is linked to hot, cold is linked to cold. Possible? Could it be the pip valves at the top of the heater? I don't think we touched those, but I'll ask my friend if they were changed out. Could it be one of the shower valves somehow forcing cold water into the hot water lines?

Good thought but no. we have both in and out lines off the top, where they were before.. the symptoms match what we think might happen if the cold water pip (tube) was broken and it was pulling water from the top, but the pip tube seem to be fine, and the water line into the house heats up when we run the hot water setting, but the hot water seems to disappear somewhere between when it goes from the heater, into the house...

Are you USA?

Quote:

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hot water comes out of heater through heater drain,

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All water heaters (as far as I know) have cold into top and hot out of top. Drain is at bottom.

Cold comes into top but is taken to bottom of tank. Hot comes out of top. As hot water is used (out of the top) the cold water that replaces it goes to the bottom. The drain is use for draining the tank only. If you are taking hot out of the bottom, the cold water is coming in the top and simply going out the bottom.

If you are not USA, then water heaters may be constructed differently. Look at the top of the tank, one pipe should be labeled cold and one labeled hot.

PS
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