Hi,
We just hired a company to rough in the plumbing for our unfinished basement and since they completed the work, we've had issues with our hot water. It starts hot, then after about 15 seconds, it goes warm and doesn't get hot until we turn off the tap for a while.
We had someone come in and look at our hot water tank and we did end up having a faulty thermostat in our upper element and that was replaced but we still have the same issue. The hot water tank is a 60 gallon tank that is less than 4 months old.
I'm no plumber but I went to take a closer look at the rough in that was done and noticed that on the shower rough in, the hot and cold pipes (1/2 " Pex I think) are both hot. Is it possible that somehow the shower faucet was not installed right and is having the same effect as cross piping the hot and cold or is it normal to have a cold pipe hot when connected to a one piece shower faucet?
I am going to call the company that roughed in the plumbing tomorrow but wanted to post to see if my findings were normal in case they come back and say it must be the hot water tank.
TIA.
Ryan

You are getting h/c water mixed up through the rough in valve.

Some rough-in valves, like single handle Delta, will allow cold water to hot side because they have no interior parts (mixing cartridge) installed. Until you install actual functional cartridge, cold water will flow into hot water side.

Mixing cartridge is not installed at the time of rough-in; will be installed after walls are tiled. It is supplied with the rough in but in separate box with the trim.

To fix this problem: install mixing cartridge...

Quote:

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Originally Posted by Milo Dolezal

You are getting h/c water mixed up through the rough in valve.

Some rough-in valves, like single handle Delta, will allow cold water to hot side because the have no interior parts (mixing cartridge). Until you install actual functional cartridge, cold water will flow into hot side.

Mixing cartridge is not installed at the time of rough-in; will be installed after walls are tiled. It is supplied with the rough in but in separate box with the trim.

To fix this problem: install mixing cartridge.....

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Thanks for the quick response. Your reply makes sense. It seems odd that this mixing cartridge wouldn't be installed during the rough in as I would think crossing the hot and cold pipes wouldn't be a good thing. This would also explain why first thing in the morning when you turn on the cold tap, it is hot for about 15-20 seconds...

Delta cartridge is not installed so heat won't damage cartridge during soldering.

Milo is quite correct. The cartridge is usually NOT included with the rough because it could get damaged or lost during installation.

Just coincidentally: It is 7:00 PM New Year's Eve. I have just come back from inspecting my friends house. She called me because she had "...a big problem....": hot water fluctuating with cold in her master shower!

I asked her if she has done any plumbing work in her house recently. She told me she is remodeling maid's shower. Bingo ! I looked inside and indeed: Delta single handle rough-in body installed with Delta dummy cartridge ! Here is where I immediately remembered this thread...

I slipped in real, fully functional, cartridge. Big smile and warm hand-shake followed...

Oh well, that's what are friends for... :D

Milo