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Old 01-08-2011, 03:32 PM   #1
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CPVC Installation Questions


The girlfriend and I have purchased a 130 year old Victorian home in Maryland which we are renovating. The heating/air system and electrical have been updated, so now it's on to the plumbing. The DWV system was pretty straight forward and is complete. We've moved on to the water distribution system and despite considerable online research, we still have a number of questions. (More specifically, "I" have a number of questions. I suffer from mild OCD, so I need to know the EXACT right way to do something before I begin. It's terrible, trust me...lol.)

After a short and expensive trial with Pex, we've decided that we're going to install CPVC. We prefer the cost, ease of installation and finished appearance of the CPVC over other materials. Here are the questions that we've come up with so far. Any help/insight is always appreciated!

1) From what I can tell, the service line to the house is polyethylene tubing. (1" blue flexible tube) The house is on a crawlspace and there is a square "boxed-in" section where the service line sticks up about 4" out of the ground. There is a platform that has been built above this boxed-in section where the water heater will be placed. I currently have a plastic (nylon?) Watts barbed x 3/4" MPT fitting stuck in the PE tube with a hose clamp on the outside. My thought is to screw a 3/4" special female CPVC adapter (with the rubber gasket) onto the Watts fitting. I've read that there are certain instances where female adapters don't work well, but since this is cold water, I should be fine, correct? Also, since the adapter has a gasket, is teflon tape/pipe dope unnecessary? Is there a preferred method to make this connection?

2) I've decided to use Flowguard Gold CPVC from Charlotte Pipe. From what I can tell, our local code allows the use of the yellow Flowguard Gold One-Step CPVC cement. Speaking from experience, would you still recommend using a cleaner, primer, both, or just rolling with the cement on it's own? Also, when using the Flowguard tube/cement, does it matter what manufacturer of fittings I use? There are no plumbing supply stores around, so I have to rely on Lowes/Orange Barn for my fittings.

3) One of the selling points that caused us to experiment with Pex was the application of the homerun manifold system. We like the idea of consistent pressure to the fixtures, faster hot water delivery and the ability to turn off individual fixtures without shutting off water to the whole house. I've decided to replicate the system in CPVC using three remote manifolds. (The house is three story and each floor would have it's own manifold) I'd run 3/4" hot and cold "mains" from the first floor to the second/third. Each floor would have 3/4" ball valves on the mains and then a manifold composed of 3/4" to 1/2" reducing tees and 1/2" CPVC ball valves for the individual fixture shutoffs. With the exception of cost, what are some of the considerations with this type of setup? Any thoughts or suggestions on the best way to implement the system? (ie: Should I leave extra space between the ball valves in case one would need to removed/replaced?)

4) When connecting an electric water heater, the CPVC can be connected directly to the heater, correct? I installed a dielectric heat trap nipple on the hot/cold ports. I was going to install 3/4" MPT transition adapters on the nipples, but am unsure about where to go from there. I obviously need to be able to disconnect the water heater from the system for maintenance. My current thought process is to install a threaded union (w/ rubber gasket) above each of the transition adapters. That way I can just unscrew the union and slide the water heater out. Any comments on this approach or other suggestions?

5) Since the house is 130 years old, it has lap siding nailed directly to the studs. The siding is in poor shape and is certainly not water tight. We will be installing sheathing and new siding in the spring, but until then, we cannot insulate these walls. (The insulation would get wet and mold) Taking this into consideration, what are some good measures to take to prevent the CPVC from freezing this winter? We're going to install a pipe heating cable on the section of CPVC below the water heater (in the boxed-in section), but we obviously can't do the same for inside the walls. I was considering buying a batt of inexpensive insulation and insulating the wall cavities only where the pipes are running. Thoughts on this approach? Would the foam pipe insulation sold in the big box stores help if used in conjunction?

6) Any recommendations on fixture stop valves? What are your feelings on the different types? CPVC solvent weld, compression or go with a MPT CPVC adapter and then a threaded stop valve?

7) Last topic/question, promise. Teflon tape vs. pipe dope? In what cases would you use each? (Assuming the pipe dope is CPVC-safe)

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Old 01-08-2011, 07:16 PM   #2
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CPVC Installation Questions


honestly, i think it's a mistake to run CPVC pipe. Especially when considered next to PEX, copper, brass, galvanized... almost anything other than vinyl tubing . If you insist on doing it, and the AHJ allows one step, use cleaner on any dirty pieces of pipe you glue. Don't use the "special female adapter" b/c it's a matter of time til the rubber gasket fails. For male and female threads only use the brass threaded fittings. For valves install real brass ball valves, the plastic ones tend to freeze after a short period of time. I also wouldn't do a manifold setup with it. The big selling point on this way of installing pipe is the lack of fittings that you get when you do it in PEX. Obviously you won't be able to achieve that with CPVC. When you connect to the water heater you need to have a union within the first 12" of piping. Use a brass one, not a plastic one with a rubber gasket (for the reasons i said above). Best idea IMO, reconsider the PEX. If you don't think you're able to diy it, get some quotes to have it installed properly by a contractor

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Old 01-08-2011, 08:32 PM   #3
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I'd like to hear more about your expensive experience with pex. Doesn't sound good. I think for the DIY'r its the product of choice, cpvc is almost nonexistant in my area. But if your using it, avoid plastic female adapters. They will most likely split over time. Put a brass ball valve on your supply instead, then a brass male adpt. I always dope and tape threads too. I guess its a personal thing.
Since I refuse to put in cpvc, I'll let someone else explain the glue process.
When it comes to sizing your lines, you need to know your water pressure and fixture units. Hate to see people guess at the pipe sizing.
IMO, avoid any plastic valves and threaded fittings.
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Old 01-08-2011, 09:44 PM   #4
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I agree with those guys when installed Properly I like Pex. CPVC is also easy as long as you are careful and plan everything out. It is not as easy to run it through joist as a roll of flexible pex is.

My biggest thing that jumped out was the "Blue Polyethelyne" that you said was your main water service. Sorry but you are most likely wrong here unless your Black pipe has faded. My guess is you have Poly Blu. If it is a light color blue that I would recommend loking into a home warranty (I have a company that cover exterior sewer and water if you need it e-mail me) that covers your exterior lines. As they say... It is not a question of if they will fail but when it will fail.

This is bad
http://www.polybutylene.com/poly.html

This is good
http://www.amazon.com/Cresline-Plast.../dp/B000HE6PA8
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Old 01-09-2011, 02:35 AM   #5
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First of all, thanks for the responses! I'll preface my follow-ups by stating that I'm not interested in getting into a debate about the different piping systems. (CPVC, PEX, copper, etc etc etc) It's my belief that every system has strengths and weaknesses and that each installer will decide for themselves which system is best. Local restrictions and water conditions also help with the decision. For example, our water contains a high level of chlorine which is a known issue for most PEX systems.

the_man, thanks for the advice on the special female adapters and the ball valves. I've decided to replace the nylon barbed fitting connecting the town supply with a brass version. I'll then use a CPVC transition adapter with brass shutoff valve to start plumbing the house. In regards to PEX, the bigger selling point for us was the ability to turn off individual fixtures from the manifold and the speed at which hot water could be delivered. (Not having joints in the walls was a bonus) I've decided to modify my manifold design slightly. Instead of each individual fixture having a shutoff (ball) valve, I've scaled back to installing one brass valve per main (hot/cold) per floor. I'll also take your advice and install brass unions at the water heater instead of the CPVC versions.

TheEplumber, the PEX experiment was fun to say the least. We ordered about $1400 worth of supplies - ViegaPEX and PEXPress valves/fittings. We were disappointed to find that the PEX tubing was less flexible than we read/expected and was a monster to work with. We were not happy with the appearance of the final result either - not very professional/clean looking. The manifolds are beautiful pieces of equipment, but everything is cast together. If you have one small problem with the manifold (ie: a crack), the entire thing needs to be replaced. That equals no water for the house until the replacement is received. Since the PEX system that we were using is proprietary, any repair parts would need to be ordered. With CPVC, if something requires replacement, I can run out to Lowes/Home Depot and buy the necessary supplies. I enjoy that peace of mind. The PEX supplies were all returned. With regard to the sizing of lines, I'll be running 3/4" mains throughout with 3/4" supply branches to the washing machine, soaking tubs and hose bibs and 1/2" supply branches to everything else. These sizes should be sufficient for their uses. Duly noted on the plastic valves/threaded adapters... these will all be brass.

Docwhitley, thanks for the great info on polybut vs polyethylene. Upon further inspection/research, I now believe that we have an EPDM rubber service line on our hands. The tube feels, compresses and cuts like rubber, so I'm fairly certain it's not polybut. We added a home warranty when we purchased the house, so we're in good shape in that regard. Thanks again!
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Old 01-09-2011, 04:54 PM   #6
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Originally Posted by Pittsville View Post

Docwhitley, thanks for the great info on polybut vs polyethylene. Upon further inspection/research, I now believe that we have an EPDM rubber service line on our hands. The tube feels, compresses and cuts like rubber, so I'm fairly certain it's not polybut. We added a home warranty when we purchased the house, so we're in good shape in that regard. Thanks again!

Double check that warranty and make sure it covers that pipe. Some dont... Mine Didnt.
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Old 01-10-2011, 02:17 AM   #7
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1/4 Turn Shutoff valves and CPVC...

I've read conflicting opinions on the topic mentioned above. More specifically, whether to use compression valves or CPVC cement-on valves. I'd like to gather your thoughts on the subject.

For ease, I would just install the CPVC cement-on valves and be done with it. The issue is that the current plumbing will be changed again in a few months when we remodel and I'd like to be able to re-use the valves. This is why the compression style are very appealing... I just unscrew and move them. ($6-8 per valve in savings)

----------------------

Also, on the subject of CPVC/brass transition adapters...

Do you see any issue with using 3/4" male brass transition adapters to connect an inline whole house water filter that has a plastic housing/threads? Any chance of developing a leak strictly due to the brass/plastic connection? (Assuming pipe dope is used to seal the threads)

Last edited by Pittsville; 01-10-2011 at 02:26 AM.
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Old 01-10-2011, 10:28 AM   #8
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Pittsville,

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Originally Posted by Pittsville View Post
With regard to the sizing of lines, I'll be running 3/4" mains throughout with 3/4" supply branches to the washing machine, soaking tubs and hose bibs and 1/2" supply branches to everything else. These sizes should be sufficient for their uses.

Interesting. I was talking to a plumber the other day about removing our gray PB pipe. I asked about upgrading the 1/2" pipe to clothes washer and tubs to 3/4". He said the larger pipe would not help with more water volume to the washer or tubs. Something about the size of the valves in the fixtures. Should I find another plumber?
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Old 01-10-2011, 11:05 AM   #9
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Pittsville,




Interesting. I was talking to a plumber the other day about removing our gray PB pipe. I asked about upgrading the 1/2" pipe to clothes washer and tubs to 3/4". He said the larger pipe would not help with more water volume to the washer or tubs. Something about the size of the valves in the fixtures. Should I find another plumber?

In this area a lot of houses have 1/2 inch lines feeding the entire house. Your plumber was right in the fact that theoretically you will not get more water because of the valve size... If that was the only thing working. Now what I have learned is that if I run 3/4 inch main line up to the area (For example-3/4 going to bath and 3/4 to kitchen) and then branch off of the 3/4 to half inch to feed the individual fixtures then you will not have a temperature fluctuation when someone does dishes while you are in the shower. I highly recommend 3/4 main line feeding all of the rooms!

You can reuse the glued valves by cutting the pipe and using a coupling.
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Old 01-10-2011, 11:44 AM   #10
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Quote:
Originally Posted by Earnie View Post
Interesting. I was talking to a plumber the other day about removing our gray PB pipe. I asked about upgrading the 1/2" pipe to clothes washer and tubs to 3/4". He said the larger pipe would not help with more water volume to the washer or tubs. Something about the size of the valves in the fixtures. Should I find another plumber?
There are frictional losses in the run and flow losses at turns (unless you have PEX with no elbows at turns). Having a larger diameter pipe for trunk lines will help with water volume. Especially if you're taking a shower and someone flushes a toilet on the same trunk line if you have a trunk and branch configuration.

HRG

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Old 01-10-2011, 12:52 PM   #11
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I plumbed my house with CPVC (actually the same brand you intend to use). I used the yellow one-step solvent. No issues at all. Plastic female adapters are not code compliant. I also did not use any plastic valves. I'll never use copper again.
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Old 01-10-2011, 02:38 PM   #12
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You can reuse the glued valves by cutting the pipe and using a coupling.
Doc, my concern was that I wouldn't be able to flush the line after I made a repair/change with a cemented valve. It seemed to me that debris would get caught in the valve when I re-pressurize the line. Am I wrong here?
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Old 01-10-2011, 02:43 PM   #13
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Originally Posted by md2lgyk View Post
I plumbed my house with CPVC (actually the same brand you intend to use). I used the yellow one-step solvent. No issues at all. Plastic female adapters are not code compliant. I also did not use any plastic valves. I'll never use copper again.
md2lgyk, thanks for the feedback! I take it you plumbed trunk/branch? If so, have you noticed any changes to pressure/volume when using a fixture (say a shower) when another fixture on the trunk comes into use (say a toilet)?
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Old 01-10-2011, 03:32 PM   #14
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To be honest Pittsville in all the years I have been doing this I do not have a problem typically with debris clogging valves. I did hire a guy that ALWAYS had a problem when he had repairs with fill valves getting clogged... I gave a lesson and he has not had a problem since then.... So here is what I do.

Drain the House at the lowest point possible and then make the repair.
I turn off all the valves on the water closets (Toilets)
Now the important part! When you restart the water do it slowly and allow the water to flow out the lowest fixture which is usually a sink. Next have all of the sinks and tubs open full blast as you turn the water on all the way. This allows all of the water to be flushed out of those larger openings. then I turn on the water closets and flush them 2-3 times.

Takes a little time but I want to make sure I do not get a call back. I also prefer 1/4 turn valves
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Old 01-11-2011, 02:13 AM   #15
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Double check that warranty and make sure it covers that pipe. Some dont... Mine Didnt.
Assuming the tubing is indeed EPDM, are there any issues with using this material as the main water service line? The stuff had already been installed when we bought the house and we know very little about it.

Also, I found a plumbing supply store today and picked up a 3/4" barb x 3/4" MPT brass fitting to replace the existing nylon one. Two questions regarding the fitting:

1) Any reason to believe that the fitting would be un-safe for potable water? I've heard that some fittings can leach lead into the water supply.

2) Considering the flexible nature of the service line, are there any other suggestions for making the connection with the distribution plumbing? Or is the barbed/threaded brass fitting the way to go?

Thanks again everyone!


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Last edited by Pittsville; 01-11-2011 at 02:23 AM.
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