School me on Pex

[Innov8tive1]

So after an extensive re-plumb of my water system (well water with multiple different filters etc.) with PVC pipe, I saw that Canadian Tire had a Pex crimper on sale so I went and bought it and a few fittings to start with. It is my understanding that Pex is THE way to go when it comes to plumbing these days and I will be undertaking many other plumbing jobs in our house in years to come. So aside from the crimp tool and a good tubing cutter, what else am I likely to need to start working with Pex?

 

[lotsoftools]

The only thing I know is that one brand of crimper will not work with all types of connectors, so make sure you get the right kind when it comes time to buy

 

[theoldwizard1]

So aside from the crimp tool and a good tubing cutter, what else am I likely to need to start working with Pex?

Aside from fittings and crimp rings (make certain you get the kind that are compatible with your tool) about the only thing I can think of is a tool to remove improperly crimped rings.

My son redid his house a couple of years ago. For "existing" plumbing redo, it may actually be easier to use straight pieces and elbows. Kind of expensive, but still easier for the average guy.

The big coils of PEX have a "memory" in those curves !

 

[Jackfre]

I remodeled both of the upstairs bathrooms in our home, which we sold earlier this year. They were back to back and had pretty much identical lay-outs. I fed the piping up thru the common wall. I did the downstairs and upstairs hall bathrooms in pex. I was careful to use as few fittings as possible in the piping system due to their dramatically reduce diameter. The master bathroom was done the following year and due to the lay-out of the existing copper, I simply continued the use of copper for the balance of that system. I used identical shower valves/heads in both bathrooms and the showers were at the farthest point from the riser wall.

The bathroom piped with copper has substantially higher water pressure than the one piped with pex. I was surprised at the difference and I'm in the business. My advise is to be very, very careful with your layout if you proceed with the pex install. Yes, it is easier to install, but the end result may aggravate you no end.

Based upon the results of my re-pipe, I will not use pex on the bathroom remodels I'm doing on our current house, and I will be completely re-piping the building. Now, all I need is for her to agree to the lay-out so I can get started.

 

[Innov8tive1]

The bathroom piped with copper has substantially higher water pressure than the one piped with pex. I was surprised at the difference and I'm in the business. My advise is to be very, very careful with your layout if you proceed with the pex install. Yes, it is easier to install, but the end result may aggravate you no end.

Is the ID of Pex smaller than copper? Was it 1/2" or 3/4"? I would think when I re-do our bathroom (hopefully next fall) I will run 3/4" to the tub/shower and 1/2" to the sinks and toilet.
I'm wondering if it is because copper is rigid and does not expand/contract and pex does. Although, higher pressure means less volume and vice versa. Could it be that you have less pressure but more flow (more GPM) with pex?

Edit: I realize what you mean about a reduction in size with elbows and couplers.......they go INSIDE the pex as opposed to outside with copper so not only do you have the restriction of having an elbow, you also have a smaller diameter restriction there.

 

[theoldwizard1]

Is the ID of Pex smaller than copper? Was it 1/2" or 3/4"? I would think when I re-do our bathroom (hopefully next fall) I will run 3/4" to the tub/shower and 1/2" to the sinks and toilet.

That is exactly what my son did.

He did NOT "home run" the rest of the house, so he used 3/4" as the main feed and 1/2" to all faucets. The only mistake we probably made was the laundry tub faucets. They have 1/2 hard copper risers and we dropped down from 3/4" to 1/2" PEX at the elbow in front of that. The washer seems very slow to fill.

 

[Jackfre]

As pointed out, the id is the same. Given that the shower valve and head are new and identical, and to test, I swapped the shower heads, one shower to the other with the same performance, the reduced flow was absolutely due to the "bushing effect" of the few pex fittings I used. You can increase the size of the pipe to 3/4" but be aware that you will delay the delivery of hot water as you have to purge the hot line of cold water after periods of no use. Cross sectional area of 1/2" is .196 sq in, 3/4" is .442. That means over twice the volume you waste before getting hot water. It adds up. I'm a user of a tankless water heater and this is a major issue in user satisfaction with tankless. This applies to conventional tank water heaters and indirects as well. Try to position your water heater for best long term performance. Get as close to the point of use as possible.

 

[cwlo]

There are fittings that have a larger inner diameter. You have to expand the pex to fit on them. Wirsbo/Uponor. Not sure if the difference is noticeable, but its a step in the right direction.

Chris

 

[Sureshot]

Does anyone have figures on the flow rates? I am part way through some replumbing of our house. We installed a large filtration system and I want to run raw water to the outside faucets. This requires some seperating circuits in the house. I have 2 three port manifolds. 3/4 inlet and 3x1/2 out. They come off of a 3/4 horse pump with a 1" discharge. I was wondering if the outside faucets should have 3/4" pex off of normal pipe tee fitting to keep up the flow? Any suggestions?

I was also going to replumb the rest of the supply to the house off of a 4 port 3/4" to 1/2" manifold. One port to the hot water heater, one cold to laundry/kitchen, one cold to the rest of the house, and one for a faucet in pump room. This filtered water system is powered by a 3/4 horse constant pressure pump with 3/4" discharge.

Can you get a 1" to 3/4" manifold?

 

[Innov8tive1]

There are fittings that have a larger inner diameter. You have to expand the pex to fit on them. Wirsbo/Uponor. Not sure if the difference is noticeable, but its a step in the right direction.

Chris

So you don't use crimp rings with that system as I understand it. You have an expanding tool that expands the pex, you put the expanded pex on the fitting and let the pex go back to orig. size and you have a seal. A neighbor of mine was talking about that the other day. I'm wondering if that isn't the way I should have gone. Seems to make more sense to have less restriction. Putting 1/2" pex with internal fittings in where 1/2" copper was is a downgrade as far as performance.

 

[Ovidiu]

Yes, if you read some of the documentation on PEX, it will say that basically you need to go one size higher than iron/copper. If I remember correctly, iron/copper, for the sizing you get ID, PEX is OD, hence the difference.

I used 1" PEX for the main run when we redid the house plumbing, 3/4" for some of the bigger branches and shower and 1/2" for the rest.

 

[jvitez]

All builders use PEX here. Easier, faster, needs much less fittings than copper. Our house is about 98% PEX. PEX pipe now comes in blue, red, and white. I wish I'd know about this when we built as I would have spec'd color coded pipe. It's great looking at newer jobs where you instantly know which pipe is hot and which is cold.

There are 3 ways to crimp PEX.

1. The absolute best is the expander type, which is only used for Wirsbo branded ProPex pipe, fittings, and rings.

http://www.pexsupply.com/ProPEX-Expander-Tools-Heads-31000

It expands the pipe, and the "memory" of the plastic squeezes down hard enough to make a permanent connection. In tests, the crimped fitting was stronger than the pipe itself! And the best thing is is doesn't reduce the ID so no reduction in flow. You can use other fittings with Wirbso pipe, but not the other way around.

2. PEX crimp rings. These are copper rings that are squeezed onto the fitting that sits inside the pipe. Pros: crimps rings themselves are cheap. Cons: you need a crimping tool for each size pipe you're using, so one for 1/2", one for 3/4", etc. The tools is less expensive than the expander tool, but more than number 3. Some have long handles which make crimping easier but more cumbersome in tight quarters.

http://www.pexsupply.com/PEX-Crimp-Tools-Rings-694000

3. PEX pinch rings. These are stainless steel rings that squeeze onto the fitting, being held together by the "spring" of the bent metal. Pros: you can remove the ring by popping off the flange with a screwdriver if you need to redo anything, though you can't re-use that piece of pipe. Crimping tool is different than 1 or 2, but only one tool for all sizes of rings. Crimping tool won't release until you've squeezed hard enough to properly pinch the ring. Cons: the rings themselves are about twice the price of copper crimp rings, and the crimping tool can be rather short. I about popped a hernia trying to crimp an undersink fitting, lying on my back in a tiny cabinet. I couldn't get great leverage with a short handled crimping tool.

http://www.pexsupply.com/PEX-Clamp-Tool-Clamps-360000

I use pinch rings for my homeowner use. I'd rather pay more for the rings than have $ sitting in crimping tools I'd rarely need. But if I was doing large project, I'd be sorely temped to use the Wirsbo system.

Resistance to flow in a pipe is inversely proportional to the diameter. IIRC the formula is radius to the power of 4. Inside pipe fitting do increase resistance so it's better to minimize them, but since the fitting makes up only a small percentage of the total length it's not as much of a problem as you'd think. So a 3/4" PEX pipe with a bunch of fittings (they're 1/2" ID) will still flow more than a 1/2" Wirsbo pipe.

 

[Innov8tive1]

In viewing those 3 options I think I made the right choice for myself. As a DIY homeowner I think the rings are the way to go. Cheaper than the cinch clamps (albeit not reuseable) and just as effective.
The expander type would never pay for itself in my toolbox. For a professional I could definitely see it as a worthwhile investment.
Thank you for the comparison.

 

[Alchymist]

Three years ago I picked up the PEX crimper for the copper style crimp rings. Came with 3 dies, 3/8, 1/2, 3/4, crimp gauge, pex tubing cutter and ring cutter for $75.00. Did a lot of re-plumbing in the old house we just bought. Ran 3/4 from tank (rural, submerged pump) to the water heater and the manifolds (hand made with 1/2' ball valve shutoffs). Everything else was run in 1/2". Plenty of flow in all fixtures. Local supply houses all carry the copper crimp fittings, not many the expansion type. Never looked back.

 

[Larwyn]

I ended up buying the 1/2 inch crimping tool and crimp rings when one of the connections to the water heater on my 5th wheel travel trailer started leaking. It came in handy several times and I recently used it to put hook up the ice maker and an indoor faucet in the garage. When I discovered pinch rings, I also bought that crimping tool (on clearance) and a few of various size pinch rings. I have only actually used that one once and that was to connect a bit of soaker hose to a brass pex adapter for someone else, but it worked a treat for that purpose though.

I'm glad to have the PEX option and I usually turn to it when I have to do any new plumbing.

 

[Fitzgerald]

Health question for everyone:

My brother-n-law is plumbing his house and we were discussing the idea of PEX
vs. copper. He has plumbed many of his rental homes, so the simplicity of PEX isn't a consideration.

Anyway, to my question. Does anyone have any concerns about the fact that this is a plastic? I read more and more about plastics breaking down and getting into our bodies (especially when the water is heated).

Copper on the other hand naturally kills some bacteria (many hospitals are starting to use in for handrails and door knobs).

I haven't worked in the construction field for quite a while now and the magazines/TV shows I watch never address the issue.

-Thanks