Installing a new gas water heater - expansion tank question

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vpn33

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Hello all. New here but have been picking up some tips and thought I would make a post. I am replacing a 17 year old gas water heater and it seems pretty straightforward. I have done a couple of electric ones before so the gas is really the main difference. I am likely going to get the Rheem 12 year 50 gallon tank at Home Depot. My other local option is A O Smith at Lowes but they just have the 9 year in stock and the Rheem has a brass drain so maybe it is higher quality. It is about the same height as the current one so I should be able to put it right in place and connect the exhaust to the current setup. Actually, the current tank sits about 5 inches away from the wall and if I push it back a couple, it would line up perfectly without needing that bend in the pipe. It currently has flexible copper lines from the solid plumbing to the tank which I will replace. Do you recommend the corrugated stainless lines (not braided) over the copper? I will also replace the gas line as well. I suppose I should put this in a pan (even though in the basement) and I will need to strap it to the wall.

There currently is no expansion tank and I want to install one without soldering or modifying any of the existing solid plumbing. I know I will have to put a tee either on top of the tank or coming off of that shutoff from the cold line. Will it work fine to just get an expansion tank bracket, mount it to the wall, and run another one of those flexible lines from the tank to the tee? Any other better ideas, let me know. Thank you.

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Terry

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I normally pick up corrugated copper lines though the stainless corrugated work too. There is no need for tape on the threads as there is a rubber washer on the ends which does the sealing. The straight threads to snug them up do nothing for the seal anyway.
If you expansion tank is supported, then a flex line to it is fine.

 
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vpn33

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Hey thanks for the info. So I can just get something like this and mount it to the wall with that flex line? What kind of tee would I use, a brass one? Does it matter if I put it on the tank inlet or right after that ball valve coming off of the supply pipe? It sounds like a 2 gallon tank is adequate for a 50 gallon water heater but for $10 more, is it a good idea to just go with a 5 gallon?

Another thing I never really liked was how the gas line is run to the current tank. Is this configuration fine as long as I get a slightly longer gas line and maybe loop it around instead of having these tight turns, or do you have a better idea? Sorry for all the questions but I am ready to do this over the weekend so if you have any other tips or if anything in my original post doesn't sound like a good idea, let me know. Thank you for reading.

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Sylvan

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White Teflon tape on natural gas is a no , no

Drip legs are also not allowed in most cases that natural gas is supplied

Also all water heaters and boilers in my area need to be piped in with hard pipe not flex's
 

vpn33

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Wow, I never noticed that, but that does look like white teflon tape that they already had there. I am aware of that being a no no because I had a propane smell in my camper and after investigating, I found that someone had used teflon tape on one of the gas lines. Is pipe dope or tape for gas lines better?

I don't know about the drip legs not being allowed but they are currently there. I had that furnace installed less than a year ago and everything was the way it is now so I would have thought that the inspector would have mentioned if they had installed that incorrectly. Also, I have done some brief research and found that flex connectors are used in seismic areas so maybe that is what is going on here. Anyways, do you think just having a slightly longer flex connector with less bend will be fine, or would it be worth it extending the pipe from the shutoff and putting a 90 to clear the furnace and then attaching to the water heater? Or maybe just leave that part alone and run a longer nipple out of the water heater and put a 90 so the flex line isn't as long?
 
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Terry

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The Seattle area is a known earthquake area. There have been enormous quakes here. Not in my lifetime, but still some good ones to let you know a big one is waiting.

The drip legs are good here, and so is the flex. I've been using pipe dope on gas fittings. If you want a shorter flex, then adding the 90 and length of pipe will work.

https://www.barnesandnoble.com/w/rainier-erupts-thomas-p-hopp/1123248663
 
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vpn33

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I appreciate it. I will just push the new tank a little closer to the wall so the exhaust pipe lines up, put it in a drain pan (unless that is not a good idea for a basement), strap it to the wall, and maybe add a 90 to the pipe so the loop is better. And as far as the tee for the expansion tank, I would imagine it would be brass, right? And the TPR currently just drains into a bucket since this is in a basement with no floor drain. Is that the way to do it? Thank you for the help!
 
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jadnashua

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FWIW, the TPR should not regularly open...it is a safety device, and except when you manually open it, it only opens upon a system fault. Code also wants it terminated fairly close to the floor, and a bucket underneath could cause it to be in the water, again, not a good idea.

If there's nothing around that is likely to be damaged, or you can't run the pan's drain somewhere useful, a pan may not make a lot of sense.
 

vpn33

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Mine has terminated into a bucket since I have lived here for the last 12 years and within the last several months, it started spitting in the bucket so I knew something was wrong. I just thought of a drain pan in case there is a slow leak or something that it would contain it for a little bit and maybe I would catch it before it overflowed, but I see what you mean, I guess it won't do much good. It won't hurt though, right? We'll see.

Anyways, I just went to buy the tank and expansion tank and they did not have any brackets so I ran my idea past the guy at the store. He told me he has always just run a tee off the tank with a short piece of pipe and a 90 with tank screwed into it (like in the image below). I have seen all kinds of setups like this when I search online so that seems pretty common. I don't like the idea of it being fully supported by the pipe though in case it fails, so if I just put a small block of wood or something between the horizontal pipe and tank to support the weight, will this be a good setup? He told me to get galvanized pipe so I picked that up too. Is that going to be fine or is brass better? After doing some research when I got home, I am confused as to whether you can mix galvanized and brass/copper so now I don't know if this is right. I plan to either connect using the copper or stainless corrugated pipes. Thank you.


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Terry

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I use brass for those fittings, and some plumbers use galvanized.
Brass will last for several water heaters.

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vpn33

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Ok maybe I will go back and get brass then. So do you think that setup with a brass line off of the tee as shown about but with a block under it to support the weight better than mounting on the wall with a flex line? Is that how you would do it?
 

Sylvan

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The reason some inspectors do not want a drip leg is it is considered a future connection

Natural gas does not have high moisture content as it had decades ago so the drip leg is not required

Nabisco in Brooklyn had in house staff installing gas lines outside and had drip legs I asked the chief engineer why he had them and he said well they have them in doors in most locations

I explained they were used in older times to collect possible moisture n the gas and impurities such as cutting oil so the drip leg was supposed to catch any foreign mater not to jam up the orifices

Placing a gas leg outside where it can possibly freeze shows that many installers lack knowledge of local codes and never ask why are they used in the first place

Here is a perfect example

A 24 year old wife was making pot roast for her family and she cut off a piece of the roast and placed it into the pot her 5 yr old daughter asked "mommy why did you cut a piece off " and the lady said because my mother always did that so the little girl asked her grand mother why she cut off a piece of the pot roast and the grand mother said because my mother did it

So thankfully there was the great grand mother and 2 generations decided to ask the great grand mother why she always cut off a piece of a pot roast before cooking it

The old lady smiled and said "Because I never had a pot big enough to place the roast in"

Same thing seeing what someone else did on an installation and people may think its the right thing to do

Rather then use Teflon tape on gas I use pro dope or rector seal or other type of joint compound
 

vpn33

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Ok, I have the brass fittings and will do it the way you show in that picture, Terry. The guy at the other store I just went to suggested that too. He also said a 2 gallon is adequate for a 50 gallon tank and then it wouldn't be as heavy, but said putting a block of wood under the pipe to support it will be fine too. Should I just stick with the 5 gallon? Thanks for all of your help.
 

jadnashua

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There are calculators that will tell you which sized tank you need. It depends on your incoming water temperature, the temp you have the water heated to, and the volume of the tank. Bigger means the bladder gets distorted less, so it MIGHT last longer (but cost more) and, will be heavier as it fills if it failed.

You might make that 90-degree elbow a T and extend it out to a shutoff so you could drain it if it failed. Otherwise, unless you drain some from the WH, it will just drain it all on the top when you remove the failed tank.
 

vpn33

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That is a good idea about the drain. I will just keep the 5 gallon then since the block I put under the pipe will support it so I guess it doesn't really matter.

While on this subject, I wanted to ask about venting this. I can push the tank a couple inches closer to the wall so it will line up with the vent above and eliminate that bend that currently comes out of the tank. Is that 3 inch straight pipe that is there now the proper kind, or should there be a different type of straight pipe to connect the two? What is there now just looks like the thing kind you run for ductwork.
 

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You will get rusty water with black fittings when faucet is just turned on. Water heater flue piped into the bottom of the flue i don't like it and not code in saint louis. Should have a tee what ever size 5-6" cap on bottom and water heater piped in the side of the tee that way there is a clean out.
 

vpn33

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You will get rusty water with black fittings when faucet is just turned on. Water heater flue piped into the bottom of the flue i don't like it and not code in saint louis. Should have a tee what ever size 5-6" cap on bottom and water heater piped in the side of the tee that way there is a clean out.

I am sorry, I don't know what you are referring to with this. Rusty water from what? What black fittings?
 

vpn33

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Just thought I'd report back here. I got it all set up last night and it works fine! I do have some small drips in the brass fittings though so I am going to take it apart today and use pipe dope instead of the teflon tape and hope that seals it up. Other than that, all seems well. Thanks for all of the help.
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jadnashua

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Many of those hose fittings have a gasket in them...using PTFE tape will often CAUSE a leak. The tapered pipe joints, though, do need tape or dope (some use both). FWIW, it's not Teflon (Dupont owns that name, and does sell or make the plumbing tape stuff, it's the generic PTFE material, essentially the same, but not correct to call it Teflon, just like not all tissues are Kleenex).
 
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