PEX through attic?


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Old 03-31-24, 08:56 AM
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PEX through attic?

The house I have has two separate water heaters. One is for the home proper, the other is just for the laundry. The laundry water heater is out pending replacement. I was thinking of taking the opportunity to run a connection between the hot output of both tanks. I had the plumber prepare the laundry output with a ball valve and a threaded (capped) coupler behind it, and was going to do the same to the other. As for the connection, I was thinking of running PEX or similar through my attic, and I have come up with questions...

1: I read that PEX should not be used about 180 degrees. It does get that hot in the attics here (South) during summer. Is this going to be ok, or is there something else that should be used? (I don't want to use copper if at all possible)

2: Assuming PEX is ok, I understand there is expansion due to heat. Is the expansion permanent or does it also shrink back when cooling? It will have hot water in the pipe, which should keep the temperature consistent, just wanting to make sure.

3: Do the connectors (right angle specifically) pose any issues in attics? Or should I try to flex the pipe to avoid having to use them?

4: Any other ideas or tips would be welcome.

Thanks
 
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Old 03-31-24, 06:52 PM
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You apparently don't have a freezing issue so I don't see an issue using PEX.
The expansion when hot is minimal.
It's not like the pipe expands like a balloon and then shrinks.

I would try to install it without using any fittings in the walls or attic.
 
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Old 03-31-24, 06:54 PM
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Pex is run in attics in hot climates all the time. If you can, run it under the insulation. That will minimize it's exposure to the hottest temps in the attic, and will minimize the chance of freezing if it also gets cold there.

Most leaks from Pex (which are fairly rare) happen at connections, so avoid them when you can. They sell PEX bend supports that allow you to make relatively tight 90 degree bends without using fittings. I'd use them if you can. PEX expands and contracts with temperature so you should use the supports sold for Pex that allow the pipe to move slightly without making a lot of noise, especially when running PEX though framing members. Some areas require long runs of PEX to include expansion loops which allow the pipe to expand and contract without putting strain on the end connections.

Is there a particular problem you are trying to solve by tying the two tanks together. Seems like a lot of work for maybe not much benefit....
 
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Old 04-01-24, 04:21 AM
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Why not connect the hot water heaters hot connections in parallel at the heaters location unless heaters are located in attic?
 
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Old 04-01-24, 10:36 AM
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The one thing you have to be concerned with is light. Most plumbing PEX tubing is not UV protected. It must be run in a location that has no light. If the attic is totally dark it will be OK.
 
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Old 04-01-24, 05:09 PM
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Carbide: I'm thinking I don't want to have to lose hot water in the house from a single failure if I don't have to. I also am kinda wanting to justify replacing the water heater in the garage (only connected to the washing machine) when not many people use hot to wash their clothes and it being out for 4 months already hasn't been THAT bad. If I connect the two separate hot water outputs, I could even stall replacing it (I have everything ready there but haven't got the new water heater yet. All the gas ones I can find are 30-40 gallon tanks which is way overkill anyway.
Beelzebob: I think that's what I'm trying to do..? The plan is to have a ball valve at each water heater. The connection I want to run would be behind the valve, so shutting off a valve only isolates that tank. So if it has a problem it doesn't kill hot water for the house.
 
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Old 04-14-24, 08:52 AM
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More Questions... Sorry to pester, but I ended up getting PEX A pipe to run (haven't run it yet), but I saw this video about the connectors. It says A is the type that can be expanded, and B is the kind that uses the crimp ring. The things that connect to the PEX (elbows, etc) are the SAME? Is there a special PEX A or PEX B elbow, joint, or etc? Thanks
 
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Old 04-14-24, 02:25 PM
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Yes.... there are dedicated fittings....
PEX A uses an expansion tool to expand the pipe and a plastic ring to fit over the fitting.
PEX B uses a crimp ring system.

Did you buy an expansion gun/tool ?
 
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Old 04-14-24, 03:46 PM
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PJ. No, I didn't buy the rings for the end, or the tools for that. I only have the PEX, some of the mounting hardware, and a couple of PEX to threaded parts for the ends I didn't get the tools or ends because I only saw bags of 50 or so (I literally need TWO), and the crimpers I saw were expensive. I was thinking I might be able to rent a tool from the hardware store so I wouldn't need to buy it for one time use.
 

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Old 04-14-24, 03:54 PM
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There are Sharkbite fittings for PEX. Avoids needing special tools and fittings. If you only need a couple of fittings and they are in visible areas not likely to be damaged (garage) I would use them.
 
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Old 04-14-24, 04:36 PM
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Call around to local plumbers.
See if they'll send an apprentice over to put two ends on.
 
 

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