will copper to pex reduce water pressure?

[Sh40674]

i have a small house built in the 70's (900 sq. feet)
1 full bathroom, kitchen sink, toilet, washer, pretty basic (another toilet and sink downstairs, doesn't get used much) and a spigot outside.

i'm finishing half my basement, and i got to looking at all the copper (1/2") lines and their age. some green spots at joints where the hard water has sealed itself over time, and i decided i want to replace all the lines on that part of the basement (AFTER the water heater). i got to thinking pex would be a pretty simple, clean, and for the most part joint free way to go. here's my questions:

1. i was considering using 2 manifolds, one for hot one for cold, because they already have shutoff valves on them (copper manifolds), would this be an OK route to go?

2. will i have water pressure issues if i go from copper to pex? the 1/2" pex fittings are only about 3/8 inside at the manifolds, elbows, etc... whats the proper way to go about this if i would do it that way?

3. are you supposed to run pex right up to the faucet/shower or is there some reason you shouldn't?

i know nothing about pex, at all. i'm an average homeowner who can do copper but never worked with pex on my own home or in a house that it wasn't already installed. so basically after my utility area (water heater location) i want to go from copper to pex. where would i run into problems?

 

[sberry]

The fittings wont matter at this volume.

 

[lakeroadster]

Pressure won't change as a result of the diameter changes.

Volume (the rate of flow) will change as a result of diameter changes.

I agree with sberry. You'll be fine with what you are proposing.

 

[The Tool Tyrant]

Why would you want to change good copper over to PEX? The green at the joints is most likely from the flux used when the joint sweating was done and the flux wasn't wiped off.

'If it's not broken, don't fix it' Personally, I'd take copper over PEX any day.

 

[finn]

Agree that the green is flux residue, not signs of seepage througthe joint.

Clean it well and monitor before doing an unnecessary tear out. I don't remember what I used, but it may have been CLR.

 

[Kaizen]

At each fixture including shower you solder a fitting onto the copper, put the pex over it, and crimp it down. they do make in line shut offs for pex. I only install pex now but only as a necessity. if you don't have any leaks I would not bother. If you were going to close it all in then yeah i'd suggest it.

 

[btdobie]

A local plumber I talked to before replacing the galvanized pipe in my basement said he only does pex by special request. He still believes copper is superior.

 

[strutaeng]

Agreed on keeping copper if it is not leaking.

At my house, I sprung a pinhole leak every year it seemed like. The third leak in three years after living here made me starting rerouting lines (slab construction) in the attic with PEX. I still have one line underground that I'll reroute this weekend hopefully. My neighbors have all had similar leaks. It seems it has to do with either acidic soil or pH of the water, who knows.

My parents' home (also b. 1960s like mine) in the next city over has never had a leak in the 24 years they have been there. Their copper will probably last the 100 years the copper manufacturers claim. Mine lasted 50 years.

A friend of mine recently replaced all his copper and sewer line because he wanted to "upgrade," although I had told him not to since the copper was seemingly fine. Sewer was another story though. His house is pier and beam.

I hope this helps.

 

[59 wagon man]

copper has a 50 yr warranty

 

[strutaeng]

copper has a 50 yr warranty

You are correct. I don't know where I got 100 years. Anyways, there are many, many homes that have copper older than 50 years without an issue.

OP, to answer your questions:

1. I can't see why this wouldn't work.

2. I would up-size to 3/4" PEX up to the manifolds to account for the slightly reduced ID. The material costs will be negligible.

3. Yes, go straight to the faucet with a male or female adapter. They make copper stub out for cut off angle stops, or you can use PEX stops. To me the copper stub out look better than PEX coming out of the wall.

 

[strutaeng]

This might be useful:

https://www.huduser.gov/portal/publications/pex_design_guide.pdf

 

[sberry]

Water Conservation Properly designed PEX plumbing systems have the potential to conserve water (see Chapters 5 and 7). The flexibility of PEX allows it to bend around corners and run continuously, reducing the need for fittings; this allows downsizing the pipe diameter to 3/8-inch for certain fixtures. Home-run systems and 3/8-inch pipes minimize the time it takes hot water to reach the fixture. Lengthy delivery time for hot water represents a significant waste of water as well as energy; a problem exacerbated in larger homes. In 2002, the NAHB Research Center conducted software simulations and laboratory tests on a “typical” hot water system using a trunk and branch rigid pipe design and one that included a 3/8-inch diameter PEX home-run system. Results indicated that systems using shorter 3/8-inch runs with a home-run manifold reduced the wait time for hot water and wasted less water than longer runs of rigid pipe with many elbows and connections.

I have read the guide, it is worth the time to read and to look over some of the charts, those are well done. Take note they use 60 ft and 100.

 

[Garage Dog]

i have a small house built in the 70's (900 sq. feet)
1 full bathroom, kitchen sink, toilet, washer, pretty basic (another toilet and sink downstairs, doesn't get used much) and a spigot outside.

i'm finishing half my basement, and i got to looking at all the copper (1/2") lines and their age. some green spots at joints where the hard water has sealed itself over time, and i decided i want to replace all the lines on that part of the basement (AFTER the water heater).

Copper should last a lifetime under normal circumstances. Unless you have build-up causing restrictions inside the copper, I would suggest you re-consider the benefit of undertaking this retrofit.

i got to thinking pex would be a pretty simple, clean, and for the most part joint free way to go. here's my questions:

1. i was considering using 2 manifolds, one for hot one for cold, because they already have shutoff valves on them (copper manifolds), would this be an OK route to go?

That would be fine. You just need copper to pex adapters.

2. will i have water pressure issues if i go from copper to pex? the 1/2" pex fittings are only about 3/8 inside at the manifolds, elbows, etc... whats the proper way to go about this if i would do it that way?

Depends on how long your runs are and what the current copper size is. Are all the copper runs currently home runs to the manifolds? I have pex and have a 1" "trunk lines" running the length of the house with 3/4" and 1/2" lines branching off of that. Just pointing out there are alternatives to running all 1/2" home-runs that support better flow and pressure depending on length.

FYI - there are different types of pex and pex fittings. There is pex designed for compression rings (the ID of the fitting is smaller than the ID of the pex vs. pex designed for expansion fitting, expansion fittings have the same ID as the pex itself, thus less restriction. You need the proper tool for either one

3. are you supposed to run pex right up to the faucet/shower or is there some reason you shouldn't?

Some people prefer changing over to copper in the wall or under the floor vs. running closer to the fixtures, really a personal preference. I ran my pex near the fixtures using the proper 90* bend bracket coming out of the wall with a 1/4 turn pex shut-off valve that has 3/8" compression out, then 3/8" flex lines going to the sinks. Other places you might prefer just having a pex to copper adapters depending on what is feeding your fixtures currently. You can run pex as far as you want assuming there is a place/access to make the transition close to the fixture.

i know nothing about pex, at all. i'm an average homeowner who can do copper but never worked with pex on my own home or in a house that it wasn't already installed. so basically after my utility area (water heater location) i want to go from copper to pex. where would i run into problems?

I am not an expert but have run thousands of feet of AquaPEX and HePEX.

If you do this make sure the pex is intended to be used for "Potable" water.

YMMV,

GD

 

[Sh40674]

Thanks guys some great info! I should be clear.. when finishing that part of my basement I want to wall around my furnace and water heater area and make it into kind of a utility room, and would like all the shut offs in 1 location. It would he much cleaner looking to have the pex... if I was planning on living there forever I'd do copper but the clean look of pex will be more appealing to buyers down the road.

So things to take from this... anything to a faucet should be good to go with the reduced fitting sizes? I'm not worried about the faucets or dishwasher... my 2 main concerns are the shower/tub and the washer. Just got a new HE washer and it uses much less water than my old one, so I don't believe it will be a concern... however, will the bathtub need to be larger than the 1/2 it is now given the reduced size of pex fittings? Or will my water still come out the same in the tub/shower as it would before I switched over?

And Garage Dog, not questioning your info at all, but what is the difference in "portable water" pex?

 

[Sh40674]

Also garage dog, I would be doing the manifolds right after the water heater on the main lines which are currently 3/4 copper, nothing branching off before that. Is anyone aware of a manifold that has shutoffs with both 1/2 and 3/4 pex fittings so I can have flexibility let's say to the outside spigot and the tub?

 

[Boomer343]

Put some water hammer stops into the lines going to the washing machine. Get a good hair dryer to soften the pex a little and make it easier to work with if you buy the coils. I usually buy a couple of straight sticks as well.

I like the shark bite hot water tank connectors and also use their flex lines for water softener connections. If you use Shark bites buy their deburring tools and read their instructions.

 

[Lunker]

Thanks guys some great info! I should be clear.. when finishing that part of my basement I want to wall around my furnace and water heater area and make it into kind of a utility room, and would like all the shut offs in 1 location. It would he much cleaner looking to have the pex... if I was planning on living there forever I'd do copper but the clean look of pex will be more appealing to buyers down the road.

So things to take from this... anything to a faucet should be good to go with the reduced fitting sizes? I'm not worried about the faucets or dishwasher... my 2 main concerns are the shower/tub and the washer. Just got a new HE washer and it uses much less water than my old one, so I don't believe it will be a concern... however, will the bathtub need to be larger than the 1/2 it is now given the reduced size of pex fittings? Or will my water still come out the same in the tub/shower as it would before I switched over?

And Garage Dog, not questioning your info at all, but what is the difference in "portable water" pex?

If you have both copper and pex mixed I don't see this as more appealing to a buyer. I'd say it's a red flag a homeowner was playing Plumber.

pex isn't more appealing than copper

 

[ctgoodman]

I have my parents house that I am renting out now. It was build in the 70s as well. Over the past 10 years or so there has been a few pin holes develop in some places. I have most of the copper piping replaced with pex now and I have had no issues in the reduction in size in the ID of the pipes. It may depend somewhat on your water that may effect the long term corrosion of the copper but in my experience at that age I would be removing as much copper as I could. For me I would put in pex over copper piping. After replacing all of the toilets and showers with permanent green stains and the frozen copper pipe that split and flooded the basement. If it would have been pex it would have survived the freeze.

 

[Garage Dog]

Thanks guys some great info! I should be clear.. when finishing that part of my basement I want to wall around my furnace and water heater area and make it into kind of a utility room, and would like all the shut offs in 1 location. It would he much cleaner looking to have the pex... if I was planning on living there forever I'd do copper but the clean look of pex will be more appealing to buyers down the road.

So things to take from this... anything to a faucet should be good to go with the reduced fitting sizes? I'm not worried about the faucets or dishwasher... my 2 main concerns are the shower/tub and the washer. Just got a new HE washer and it uses much less water than my old one, so I don't believe it will be a concern... however, will the bathtub need to be larger than the 1/2 it is now given the reduced size of pex fittings? Or will my water still come out the same in the tub/shower as it would before I switched over?

And Garage Dog, not questioning your info at all, but what is the difference in "portable water" pex?

Also garage dog, I would be doing the manifolds right after the water heater on the main lines which are currently 3/4 copper, nothing branching off before that. Is anyone aware of a manifold that has shutoffs with both 1/2 and 3/4 pex fittings so I can have flexibility let's say to the outside spigot and the tub?

1. There are now far to many brands of pex that have different uses to cover here. In general pex for heating use has an oxygen barrier, pex for potable water (drinking water) does not need it. There may be other differences depending on mfg - just wanted you to know that different types of pex are designed for different applications. You want pex that is designed "for use with potable water".

2. From the info you have given, you don't necessarily have to use larger than 1/2" pex to feed the shower - again just depends on length of run, elbows, tees, other restrictions. All of my showers and tubs are fed with 1/2" in the end near fixtures, how long the 1/2" portion is run varies.

3. There are pre-made manifolds in different sizes, both diameter and number of branch outlets. The manifold you are describing can be easily made with 3/4" copper and various tees, some tees can stay 3/4" if you choose, others can be reduced to 1/2" in a variety of ways. Then you just need the appropriate copper/pex adapter to transition from your copper manifold to the various pex runs. You can put shut-off valves in wherever you want.

For that matter you can also make a distribution manifold with pex, just depends on what you are comfortable working with.

Hope that helps,

GD

 

[Garage Dog]

Here is one way a manifold can be made with shut-offs and different size pex for different runs. These all happen to be 3/4" and 1" - just a visual reference to give you an idea.

GD

 

[crazylunker]

Why would you want to change good copper over to PEX? The green at the joints is most likely from the flux used when the joint sweating was done and the flux wasn't wiped off.

'If it's not broken, don't fix it' Personally, I'd take copper over PEX any day.

Amen

 

[Sh40674]

sorry have been away for a while! garage dog, this is the type of manifold i'm looking at.. figure one for the hot, one for the cold

https://www.menards.com/main/heatin...?tid=-2854985425780303757&bargainStoreId=3040

and these are the type of rings i was planning on using (already own a crimper for them, any issue with using this style?)

https://www.menards.com/main/heatin...4449304966-c-8556.htm?tid=-673348439043155850

 

[HomeInspector]

Part of me fears that Pex will have the same fate as aluminum wiring. Made sense at the time, but whoops! To answer your question though, it will not reduce water pressure.

 

[zigzagfrog]

An acquaintance used pex when he redid the plumbing in his 100 year old farmhouse. He did it again two years later with copper. Rats have a much harder time with copper it seems.

 

[Sh40674]

Part of me fears that Pex will have the same fate as aluminum wiring. Made sense at the time, but whoops! To answer your question though, it will not reduce water pressure.

issues with aluminum wiring? ran aluminum wiring to the garage lol

 

[SALIV8]

I have copper at one place and pex at the other.

The pex has saved my **** a couple times when we lost the heat, and didn't burst because pex is able to expand, and more resilient than copper.

I like the copper also. Chicago code is copper and rural areas in Michigan can use pex.

I would be sure to follow code whatever you decide to do.