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Changing copper to PEX.

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[OP]
Newbie
Nov 4, 2015
79 posts
41 upvotes
Halifax

Changing copper to PEX.

Recently had a water leak and once I pulled the ceiling apart to get to the leak I decided it was time to upgrade the plumbing.

The current copper setup is the original from 1974, all half inch right from the meter. I'm thinking of running a 3/4 inch from the meter (it's one inch coming in to the meter) to a manifold.

My main question is can I put the manifold my crawl space? It's a central location, the water meter is currently located in there, it's heated and had lights and easy access. I'd like to have all the PEX run to a central location, the longest run from the location I want to use would be about 18 ft.

I'm located in Nova Scotia. The person I spoke to from the city referred me to the National plumbing code, I'm currently trying to find a copy.

Thanks in advance
62 replies
Deal Expert
Jan 27, 2006
17128 posts
9866 upvotes
Vancouver, BC
Before you follow the above advice, I would like to say that I've done pretty much what you wanted to do 5 years ago (except for that my house is on the other coast) and I can tell you the following:

1. Definitely follow the local building codes.
2. PEX doesn't provide any grounding as it's PLASTIC. Verify that you don't have anything grounded to the existing copper pipe. If you do, replace the ground.
3. Manifolds provide a GREAT advantage over standard trunk and branch design. Having been in the same house with both, I think I might know a thing or two about it. Besides having a central location, you can also install shut-offs to each run so that you can isolate it if required. And, by having a manifold, I've found that the water supply especially the hot water is much more balanced throughout the house if multiple people use hot water at the same time.
4. You will find a slightly longer delay in getting hot water to some locations.
5. I would run the same diameter PEX from the meter to the manifold. In your case, 1" to the manifold. Then from the manifold, go 3/4" to the hot water tank then 3/4" back to the hot water manifold and, 5/8" to the outdoor spigots. The 5/8" to the outdoor spigots are great for the additional water pressure for outdoor use - you can also do 3/4" but that might be overkill. The 3/4" to the hot water tank will allow more users to use the hot water at the same time. If you just have the same diameter pipe to/from the hot water heater as the rest of the house, the hot water pressure for 2 or more concurrent users will drop and drop fast.
6. If you can, get two different colours of PEX pipe (one for hot and one for cold)! Makes it a lot easier to troubleshoot later on if needed.
[OP]
Newbie
Nov 4, 2015
79 posts
41 upvotes
Halifax
Thanks for the advice. I'm definitely set on the manifold setup, I want the isolation incase I have issues in the future.
Got the plumbing code from the library, gathering supplies for the project now. Just waiting on my permit, I applied this morning, could take a week though.

Any recommendations for online plumbing supplies? I've got the PEX already but still need valves.
Deal Addict
Jan 19, 2011
2987 posts
1234 upvotes
I used an Atlas 6 outlet pair pex manifold.

Here is a photo of a unit very similar to my own:

Image
"The truth is incontrovertible, malice may attack it, ignorance may deride it, but in the end; there it is."
Just a guy who dabbles in lots of stuff learning along the way. I do have opinions, and readily share them!
Deal Guru
User avatar
Dec 11, 2004
10182 posts
2804 upvotes
Montreal, QC
Keep in mind that 3/4" PEX ID is roughly the same as 1/2" copper.

I'm not convinced that a manifold will result into longer delay to get hot water, on the contrary, 3/4" copper trunk will hold much more water that needs to be emptied out, especially since you can move the manifold to a central location.
Also, it will cool down way fast, it might be faster, say in the morning when the bathroom and kitchen are being used, but throughout the day, I doubt it.

A manifold will also help balancing water pressure.

I don't like the idea of a plastic manifold (and having cold right next to hot), also these tends to be quite expensive, I would rather get 2 separate all copper unit instead (and add shutoff valves if necessery)
Deal Expert
Jan 27, 2006
17128 posts
9866 upvotes
Vancouver, BC
Daijoubu wrote: Keep in mind that 3/4" PEX ID is roughly the same as 1/2" copper.

I'm not convinced that a manifold will result into longer delay to get hot water, on the contrary, 3/4" copper trunk will hold much more water that needs to be emptied out, especially since you can move the manifold to a central location.
Also, it will cool down way fast, it might be faster, say in the morning when the bathroom and kitchen are being used, but throughout the day, I doubt it.

A manifold will also help balancing water pressure.

I don't like the idea of a plastic manifold (and having cold right next to hot), also these tends to be quite expensive, I would rather get 2 separate all copper unit instead (and add shutoff valves if necessery)
Using PEX with a manifold does create a slightly longer delay for a number of reasons but one reason most people don't think about is the PEX runs tend to be a bit longer than copper runs as it's more cost/time effective to run PEX lines without 90 degree corners if possible (ie a wide turn rather than a sharp one and a joint) and a few extra wide turns here and there add-up especially on the longer runs. Also, I believe there might be less convection currents (as well conduction currents) using PEX so that cold/cool water in a hot water pipe stays cold/cool vs in copper where the pipe itself conducts heat away from the hot water and warms the cold/cool water further down the pipe along with the documented hot/cold flows within the water inside the pipe.
[OP]
Newbie
Nov 4, 2015
79 posts
41 upvotes
Halifax
My main reason behind the manifolds is to minimize concealed connections/tees and stabilize water pressures. Currently I only have 1/2' copper coming from the meter and it is routed the long way around my house (likely due to renos over the years). The line is also full of tees and they are all concealed in the ceiling with no access. With the pex/manifolds there will be no concealed joints. My runs are fairly short so im not overly concerned about the delay.

I'm still undecided on manifold type. I do like the one pictured above with the valves already on it, however copper manifolds with separate valves will likely be more cost friendly.
Deal Guru
User avatar
Dec 11, 2004
10182 posts
2804 upvotes
Montreal, QC
Looked up some numbers, 100ft of 3/4" Type L copper pipes holds 2.5 gal of water whereas 1/2" PEX holds 0.9 gal, so that's like 3x as much water.

Granted one doesn't usually have such long runs but unless your homeruns are 3x as long, 1/2" PEX with a manifold holds will result into less water to flush out than a 3/4" copper trunk.
Thus, faster hot water.
Deal Addict
Jan 19, 2011
2987 posts
1234 upvotes
CoreyH877773 wrote: My main reason behind the manifolds is to minimize concealed connections/tees and stabilize water pressures. Currently I only have 1/2' copper coming from the meter and it is routed the long way around my house (likely due to renos over the years). The line is also full of tees and they are all concealed in the ceiling with no access. With the pex/manifolds there will be no concealed joints. My runs are fairly short so im not overly concerned about the delay.

I'm still undecided on manifold type. I do like the one pictured above with the valves already on it, however copper manifolds with separate valves will likely be more cost friendly.
say no more~!

In my house, I used a twelve port (6 hot 6 cold) Atlas brand manifold very similar to the one in the photo I showed. Cost was $160 plus taxes at Lowes, but not many stores stock them, and few staff even know about them, believe it or not. I ran about 60 feet of 3/4" Pex to the manifold (via the water heater for hot, of course) and the manifold supplies the main bath walk in shower in a direct run, and everything else just has two, or maybe three shared fixtures on a run. The main bath tub (rarely used), toilet, and vanity all share a run, for example. I am very pleased with the results, and would not have done it differently.

I just added two copper four port manifolds complete with sharkbite shutoffs (4 hot and 4 cold total) at the cottage, cost $55 each I think, so cost per port is comparable. I have short runs of 3/4" from the jet pump and hot water tank to the manifolds, and three of the four ports are in use now, serving all fixtures in the cottage, once again, the shower/tub is on a dedicated run, the rest share runs. Once again, I am very pleased with the results, and would not have done it differently.

my-way-finishing-basement-cottage-2161388/ visit post #22 on page 2 for two images
"The truth is incontrovertible, malice may attack it, ignorance may deride it, but in the end; there it is."
Just a guy who dabbles in lots of stuff learning along the way. I do have opinions, and readily share them!
Deal Expert
Jan 27, 2006
17128 posts
9866 upvotes
Vancouver, BC
CoreyH877773 wrote: My main reason behind the manifolds is to minimize concealed connections/tees and stabilize water pressures. Currently I only have 1/2' copper coming from the meter and it is routed the long way around my house (likely due to renos over the years). The line is also full of tees and they are all concealed in the ceiling with no access. With the pex/manifolds there will be no concealed joints. My runs are fairly short so im not overly concerned about the delay.

I'm still undecided on manifold type. I do like the one pictured above with the valves already on it, however copper manifolds with separate valves will likely be more cost friendly.
When I put my manifold in place, the selection of manifolds in Canada was poor at best so my plumber actually made a manifold out of PEX, 'T's, and ball valve shut offs. It's not the best designed manifold in the world but it works.

Today, I would go for
* two separate manifolds (one for hot and one for old) rather than having an all in one;
* a copper manifold but would have soldered on ball valves with bleeders on every line and have an extra one at the end so that I can drain the entire system as well as possible expansion;
* a water hammer arrestor installed at the end of each manifold.
Deal Guru
User avatar
Dec 11, 2004
10182 posts
2804 upvotes
Montreal, QC
Water arrester works best next to the fixture/source of the hammer, not at opposite end.

Having ball valves with a drain is a great idea
Deal Expert
Jan 27, 2006
17128 posts
9866 upvotes
Vancouver, BC
Daijoubu wrote: Water arrester works best next to the fixture/source of the hammer, not at opposite end.

Having ball valves with a drain is a great idea
Water arresters do work best next to the fixture/source of the hammer however, at the point of installing new PEX, it's nearly impossible to tell which fixture will be the source of the problem. Speaking from experience of installing water arresters in my house before the PEX change over (ie when it was all still copper), many times the hammering is in the walls and without ripping out drywall, you can't install it next to the fixture. I've found that even having a commercial one installed in a central location (ie next to the hot water tank) improves hammer through out the system. Will it fix all hammering? No as each hammering situation is different... but it will probably reduce it.
Deal Guru
User avatar
Dec 11, 2004
10182 posts
2804 upvotes
Montreal, QC
They have these valves with built-in arrester, usually the culprit would be the fast closing valves, washing machine, toilets and touchless faucets.

Image
Deal Addict
Jan 19, 2011
2987 posts
1234 upvotes
Having done my whole house with Pex a few years ago, runs back to the 12 port manifold, I have installed no arresters, and have no issue with hammer.
"The truth is incontrovertible, malice may attack it, ignorance may deride it, but in the end; there it is."
Just a guy who dabbles in lots of stuff learning along the way. I do have opinions, and readily share them!
Deal Addict
Apr 22, 2014
3097 posts
468 upvotes
Oshawa, ON
I did a Viega manifold with enough outlets to run 1/2" to every individual outlet in the house. Code is pretty much common sense, get lots of clips to hold it in place every few feet.
Manifolds are cheap on Amazon, fittings not so much. Went to Buffalo for a big load of stuff now I have ton of bits and pieces (if you're near Oshawa PM and I can save you some $).
Put the manifold near the heater as you can get away with. You might need stainless for the first couple feet for that so you don't melt your PEX on the outlet. Use min radius brackets for making bends. Avoid crimping. Give the pipe a massage when you are doing it, it softens up with a bit of rubbing/warmth (don't use a heat gun lol, maybe just a hair dryer).
I did it all in a weekend. Pulled out the copper and ran the tube.
In retrospect, I would use more manifolds spread out, like a central one with 3/4" runs to a kitchen manifold, to the upstairs bath manifolds, to the laundry, etc. That would cost about $1000 more I'm sure. Too late now, next house lol. Also I would put the outside taps on a separate "pre-manifold" manifold with the same size as the inlet pipe so you have the max pressure possible to the outside bibs.
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Deal Guru
User avatar
Dec 11, 2004
10182 posts
2804 upvotes
Montreal, QC
Yeah mini manifolds for a group of fixtures is nice too and hose bib on pre-manifold.
[OP]
Newbie
Nov 4, 2015
79 posts
41 upvotes
Halifax
Thanks for all the input folks. I'm definitely going to avoid any crimps where i can. Still undecided on manifold type. Im going to check around locally and see what I can find.
Newbie
Oct 28, 2011
42 posts
29 upvotes
Aurora, Ontario
Just sharing of my experience

One of the copper pipe in my house has a needle hole leak, so I researched into PEX pipe vs copper pipe. When I looked in the lifetime of PEX pipe, the manufacturers homepage indicating it is 20 yr. In short, this implies that PEX can last ~ 20 yr. I immediately stop considering PEX piping as the repair requires removal of tiles, drywall, painting, mold, water damage
Deal Addict
User avatar
Dec 27, 2007
1268 posts
697 upvotes
Oshawa
Please provide the relevant data to back up your statement.
feels1 wrote: Just sharing of my experience

One of the copper pipe in my house has a needle hole leak, so I researched into PEX pipe vs copper pipe. When I looked in the lifetime of PEX pipe, the manufacturers homepage indicating it is 20 yr. In short, this implies that PEX can last ~ 20 yr. I immediately stop considering PEX piping as the repair requires removal of tiles, drywall, painting, mold, water damage
Deal Expert
User avatar
Dec 26, 2005
16945 posts
1788 upvotes
Thornhill
feels1 wrote: Just sharing of my experience

One of the copper pipe in my house has a needle hole leak, so I researched into PEX pipe vs copper pipe. When I looked in the lifetime of PEX pipe, the manufacturers homepage indicating it is 20 yr. In short, this implies that PEX can last ~ 20 yr. I immediately stop considering PEX piping as the repair requires removal of tiles, drywall, painting, mold, water damage
Well, there’s probably NO warranty provided on copper tubing. My roof has something like a five year warranty. Oh and my iPhone only has one year warranty.

bjl
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