pls advise on hot&cold water inlet piping

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Old 06-30-20, 02:01 AM
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pls advise on hot&cold water inlet piping


I am going to replace this 10+ year old water heater, and am thinking about re-do all the pipework that goes into the water heater, as shown on the picture, those copper pipes are covered with greenish corrosion.

The cold water goes from the water main to the water heater directly, the original installer made several turns on the copper pipe before it goes into the heater, to reduce the water pressure maybe?

I am going to use the 18-inch flexible pipe to connect both the hot and cold water to the water heater. Now the question is, because I am getting rid of all those copper pipes shown on the picture, and maybe it is not a good idea to directly connect the new flexible pipes to the remaining outlets in the wall. How should I run the new copper pipes from the wall outlet before it connects to the flexible pipes?

BTW, the original installer did not install a thermal expansion tank, and it worked fine for the past 10+ years. It is a condo unit, I believe there is a check valve for the entire subdivision, but not for each individual condo unit. So probably the thermal expansion tank is not needed.

Thanks!
 
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Old 06-30-20, 03:14 AM
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No reason not to connect flex pipes to wall connectors. By code you will have to add a expansion tank in cold water side . I also would add 1/4 turn shut off valves on both cold and hot water lines.
Only reason I can think of all the bends is plumber was trying to hug wall.
 
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Old 06-30-20, 04:07 AM
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Thanks for the response! What do you mean by "plumber was trying to hug wall"?

If the water from the main goes directly to the bottom of the water heater without those turns, could the water pressure be too high so that the water stream keeps pounding the bottom of the heater, which could result in a early failure of the heater? I thought that's probably the reason that the original installer made those turns, but I am a noob, have no idea.

If I connect the flexible tube to the wall outlet directly, it seems like I may also need some adapters. Pls see the picture below,

On both cold and hot water sides, the original installer added a short female PVC pipe to the wall outlet, before connecting to the copper pipe. I don't know why he did not connect the copper pipe directly to the wall outlet. The wall outlet was painted white, I have no idea what kind of pipe that is (PVC? Steel?). And how to take this short PVC pipe sleeve off from the wall outlet?

Thanks!
 
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Old 06-30-20, 05:01 AM
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Hug the wall, get closer to back wall. No idea why. Scrape the paint a little so we can see what type pipe under it. How plastic ic connected to other pipe is still a mystery. Maybe a threaded fitting under it. Should be but till you take it apart won't know for sure. don't think I have seen that setup before. Wait till some pro plumbers come in and can help better. scrape that pipe now and let us know what you find Another picture.
On hot water side I would use a shark bite fitting to make transition to your flex with a shut off.
 
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Old 06-30-20, 05:18 AM
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The expansion tank should be between the cold shutoff and the water heater.. That is, no valves or check valves between the expansion tank and the heater.

Another explanation for the extra pipe bends although I cannot read the mind of the person who installed all that: To reduce eddy currents up and down within the pipe that would "waste" some of the heat of the tank contents 24/7. So called heat trap nipples (look almost the same as ordinary nipples) at the top of the heater also cure this problem. This seems to be more of an excuse than a reason because there is heat loss up the center flue when the burner is not kicked on.

 
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Last edited by AllanJ; 06-30-20 at 05:39 AM.
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Old 06-30-20, 05:40 AM
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I looked it up regarding the "heat trap nipples", and I think you are right, most likely that's the reason for the multiple turns. Now, my only concern is, if I connect a flex pipe from the water heater directly to the main, will the water pressure be too high from the main so that it could slowly damage the bottom of the water heater?
 
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Old 06-30-20, 06:00 AM
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I am currently away from the condo so I can't scrape the paint to see what kind of pipe underneath, but I think it is probably PVC. Therefore,

Joint #1 is probably PVC cemented to PVC,
Joint #2 is PVC and copper threaded connection,
Joint #3 is copper to copper compression fitting?
The same 3 joints on the hot water side. What do you guys think?

Now, I am thinking about using a flex with sharkbite connector on one end with ball valve like this to connect to the wall outlet, which joint should I take apart and what is the best way to get connected to sharkbite connector?

Thanks!

 
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Old 06-30-20, 08:39 AM
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No. Any pressure difference between having or not having that extra loop of pipe will not affect the bottom of the water heater at the end of the dip tube.
 
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Old 06-30-20, 10:13 AM
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The pipe in use in your unit is C-PVC.

That is a C-PVC adapter to metal pipe. Can't tell if 1/2" or 3/4" in your picture.
The threaded piece is like that as it's stronger than a threaded C-PVC connector.

C-PVC connector
 
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Old 06-30-20, 10:38 AM
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The flexible SharkBite makes it really easy to install. I would use an 18" version of it, as water heaters require 18" metal pipe before converting to plastic (which is probably the reason for the loop).

I would cut the copper pipe about 2 or 2.5" from where it converts to CPVC. You only need a bit over an inch, but the extra gives you some wiggle room. Ditch the rest of the copper.

 
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Old 06-30-20, 10:43 AM
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So this C-PVC adapter was cemented to the wall outlet, right?

How do I take it off?

I mean, if the wall outlet is 1/2'' C-PVC, I can possibly get a ball valve with one end sharkbite 1/2'' nom C-PVC, the other end 3/4'' MPT, then I can connect the flex pipe directly to it. I don't need that C-PVC adapter.
 
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Old 06-30-20, 10:52 AM
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I would cut the copper pipe about 2 or 2.5" from where it converts to CPVC.
If I do that, it would leave several joints (i.e., C-PVC adapter cemented to the wall outlet, the copper pipe NPT threaded joint with the C-PVC adapter) from the 10+ year old installation, these joints may fail. So I prefer to install everything new from the wall outlet. The problem is how to detach the C-PVC adapter from the C-PVC wall outlet without damaging the wall outlet.
 
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Old 06-30-20, 03:56 PM
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So this C-PVC adapter was cemented to the wall outlet, right?

How do I take it off?

I mean, if the wall outlet is 1/2'' C-PVC, I can possibly get a ball valve with one end sharkbite 1/2'' nom C-PVC, the other end 3/4'' MPT, then I can connect the flex pipe directly to it. I don't need that C-PVC adapter.
You can't take it off short of using a hacksaw and then as a newbie you will really have a mess. The green stuff on the copper pipes is indicating leaking sweat joints, I cannot imagine a real plumber doing a job like that. More likely was done by an inexperienced handyman. If you are going to use the flex connectors with the push-on connection, connect onto the copper pipe several inches away from the CPVC pipe.
 
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Old 06-30-20, 05:49 PM
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I don't want to hacksaw the entire joint off because then there won't be too much wall outlet left. I was thinking about heating that joint up and try to separate the cpvc adapter from the wall outlet, using a heat gun. Will that work?
 
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