Hey there. Hot water side has pressure even before HW heater installed?

[Jeff R]

Hey there. Been reading your forum for a while, I'm building a house and nearing completion. So my plumber roughed in everything and then came out to give me a quote on finishing the rest out and never got back to me. I've hooked up the toilet and kitchen sink with no problem but I am curious as to why my hot water line has pressure in it and will run water, same as the cold side, even though I have not put in the water heater yet. I was under the impression the hot water side had to go through the hot water heater first. Can anybody clarify this? Was it hooked up this way to test pressure on the hot water lines?

Thanks!

 

[Reach4]

Take a look at the area where the WH will go. There is probably a pipe or flex line connecting what will be the input and output of the WH.

If it does not become clear to you, post a photo.

 

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[Jeff R]

if there is, it's inside the sheetrock. i was afraid of that.

 

[Reach4]

if there is, it's inside the sheetrock. i was afraid of that.

That would not be the case, I would not think. What do you see?

If you see only capped pipes, there could be a crossover in a plumbing fixture somewhere.

 

[Jeff R]

yeah. just capped ends of PEX where the water heater is going to be. the only thing hooked up to the hot water side is the kitchen sink and the shower valves, and they don't have any trim hooked up to them. could they be how the lines are crossed over?

 

[Reach4]

yeah. just capped ends of PEX where the water heater is going to be. the only thing hooked up to the hot water side is the kitchen sink and the shower valves, and they don't have any trim hooked up to them. could they be how the lines are crossed over?

I would think that is possible. Try closing the stop valves on the cold sides of those fixtures, and see if the hot still has high pressure flow. The bathroom lavs are not hooked up yet, I presume.

Also inspect each fixture rough in... a temporary jumper could have been put at any of them for the testing purpose that you suspect. Don't forget the laundry hookup.

 

[Jeff R]

You are correct. The lavs are not hooked up. I looked closely at the rough ins, no jumpers. The shower valves don't have stop valves on them. It's just the Delta/Masco brand sort of like this:

https://www.deltafaucet.com/bathroom/product/R10000-PX

I turned the hot water on on the kitchen sink and let it run, and held my ear up to the upstairs and downstairs shower fixtures to see if I could hear any flow. I could not, but that might not mean much.

 

[Reach4]

I turned the hot water on on the kitchen sink and let it run, and held my ear up to the upstairs and downstairs shower fixtures to see if I could hear any flow. I could not, but that might not mean much.

That sounds meaningful to me, especially if the environment is quiet.

Now try reversing that, putting your ear to the kitchen faucet.

If the inside of the house is much warmer than the incoming water, tomorrow you could also feel the cold lines that you can touch. The lines carrying water should be colder.

Regarding the shower, is there an access panel on the other side of the shower plumbing? It would be good to familiarize yourself with that.

Did you take pictures of the plumbing while the walls were open? You will the next time you have a house built.

 

[Jeff R]

I took video and a few pictures. My work is sporadic and spur of the moment, so unfortunately I was not here when the sheet rock went out. But I have video and pictures of almost everything. There's no access panels to the shower plumbing. The bottom one just has tile board covering it, and the upstairs one is open so I can get to it.

Late in the day, if I run the hot water in the kitchen sink the water seems much warmer than the water coming out of the cold side. I assume that that's because for some reason it is traveling through the walls and it's a hot summer day.

 

[Jeff R]

I just listened again to the upstairs shower fixture. It's faint, but I can hear flow versus when the kitchen sink is turned off.

 

[Reach4]

Access panel?

Often there is a closet is on the other side of the shower plumbing.

 

[Jeff R]

Access panel?

Often there is a closet is on the other side of the shower plumbing.

No access panels on either one.

 

[Reach4]

No access panels on either one.

If there is a close, you could amend that to "No access panels on either one yet".

But with no access panel, it seems unlikely that you have stop valves in there already.

Is there any chance you have a manifold system to go with your PEX?

 

[Jeff R]

I might could put access panels in. But like you said, I do not have stop valves in there. There's no manifold, either. Everything seems very straightforward. I'm just puzzled about those shower fixtures. I don't know much about them. Is there a way to manipulate them without having trim hooked up?

 

[Reach4]

I'm just puzzled about those shower fixtures. I don't know much about them. Is there a way to manipulate them without having trim hooked up?

Here is a picture of the valve that you are talking about. Somebody who did not follow your link might recognize it, and let you know if it would normally connect the hot and cold together.

 

[Jeff R]

that has to be what's causing it. can you manipulate them if there is no trim attached? seems like if i could turn them off i could test that theory.

 

[Jadnashua]

A rough-in shower valve without a cartridge or (optional on most) plug, WILL just let water cross over between the hot-cold. You have three choices...leave it as it is and don't worry about it, put a cartridge in the shower valve, or buy and put in the plug that will prevent the cross-over. That front cover just keeps water from flowing out the front, but it does nothing to block the flow from the hot-cold inlets from mixing.

 

[Jeff R]

Thanks for your help, y'all. I appreciate it.