# Is it ok to install an expansion tank right on top of water heater?



## Electric_Light (Nov 25, 2007)

Typical configuration I see is hanging down on cold water supply line with a T. 

Because of the configuration I'm working with, it would be easier if I could just use a T, then mount the expansion tank right above the cold water inlet on water heater with a T vertically so that the weight rests on the water heater itself, then have the cold water supply connect to the side.

Is this acceptable?


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## KillerToiletSpider (May 27, 2007)

What does your code book say?


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## Electric_Light (Nov 25, 2007)

KillerToiletSpider said:


> What does your code book say?


Plumbing isn't my area, so I really don't know, which is why I was asking you guys.


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## KillerToiletSpider (May 27, 2007)

Electric_Light said:


> Plumbing isn't my area, so I really don't know, which is why I was asking you guys.


Plumbing code varies from state to state, and even in state it can vary by county or township.

So what does your codebook say?


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## griz (Nov 26, 2009)

KillerToiletSpider said:


> Plumbing code varies from state to state, and even in state it can vary by county or township.
> 
> So what does your codebook say?


What does your AHJ say?


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## Tinstaafl (Jan 6, 2008)

Man, you guys slay me. :laughing:

EL is an established member here, why can't you cut him a break? Yeah, we all know that local codes vary, but you could toss him a bone with that caveat.

Or just refrain from making such posts at all.

[Hmm. I may be breaking under the strain. :shutup: ]


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## griz (Nov 26, 2009)

Hey Tin, I was attempting to make a legitimate non smart a** answer. 

Hey Grand Pa, it's late for both of us. Good Night:thumbsup:


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## Electric_Light (Nov 25, 2007)

Code thing aside, is there a practical reason not to do so?


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## Mike's Plumbing (Jul 19, 2010)

It has a bladder, I don't know what your code says but I can tell you for a fact it will work.

*Rule of thumb*
Heated water expands, going from 90 deg to 140 deg on a 40 gal tank will expand 1/2 gal. It will find a way. 

Code books are just a rule of thumb, don't worry about it, at least they can't take you plumbing license away.:laughing:

Mike


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## Electric_Light (Nov 25, 2007)

Mike's Plumbing said:


> It has a bladder, I don't know what your code says but I can tell you for a fact it will work.
> 
> *Rule of thumb*
> Heated water expands, going from 90 deg to 140 deg on a 40 gal tank will expand 1/2 gal. It will find a way.
> ...


Thank you for helpful response. I'm more on the office type stuff and really don't get dirty much, so I can be a n00b with things that's completely out of my field. 

I thought it would be just fine too, but I had a second thought about it considering being directly above the water heater might leave the expansion tank warm all the time and shorten the bladder life. 

The current install (I'm just working on my own water heater) doesn't even have expansion tank and many old installs don't, but I figured that I will add one after seeing signs of frequent release valve operation. The frequent pressurization to the point of release valve opening couldn't be good for appliances either.


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## Mike's Plumbing (Jul 19, 2010)

In Wisconsin they never go in houses- EVER.

I service houses all day long and it's very very rare I have RV problems.

If it was me I would just change out the RV and call it a day!

Mike


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## Driftwood (Feb 15, 2004)

*IN My opinion*

That's a poor place. You May not have access to schrader air fill valve on the bottom. Uni strut and clamps work well. Recently i build a small wood shelf with bracket and metal perf. tape to secure. Passed in S.F.,and their tough


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## Driftwood (Feb 15, 2004)

Mike's Plumbing said:


> In Wisconsin they never go in houses- EVER.
> 
> I service houses all day long and it's very very rare I have RV problems.
> 
> ...


 I usually see a T&P dripping before I install one,

In Wash. state, Ex. tanks are mandatory!


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## Mike's Plumbing (Jul 19, 2010)

The thing is, if I hadn't done thousands of service calls I would want to be Mr. Rulebook but man....I have seen things that are so wrong and so illegal but work perfectly.

It's like the air valve, should you have one? YES. Would I advise you do do it per code? YES. Will it work without one? YES. Will it work well without one? YES Will you have issues in the future? I doubt it.

Experience has tought me many things and I can't give you a full plumbing course on a forum, and you don't want one. The fact is things do work like this....it's water. 

Put a T&P in and go have lunch.

Mike


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## protechplumbing (Oct 10, 2008)

Yes. The further the tank is from the cold inlet of the heater the better. Colder water is kinder to the bladder inside the ex-tank. Some codes do not allow the tank to be seperated from the heater by a valve. Check 1st. I personally don't have a problem installing the tank before the cold water shut off valve provided that there is a backup thermal expansion valve that can't be isolated from the tank but I digress.....

If you put the ex-tank right on top of the heater it won't last as lond due to heating from convection. Not the end of the world though.

I highly recomed that you install a pressure relief valve as well as a thermal expansion tank. Set the relief valve a few pounds higher than your static pressure and pipe the relief valve drain to a visible location. If you ever see the relief valve dripping, you know your thermal expansion tank is bad and needs to be replaced. If you don't have said valve installed, you won't know when the bladder goes out. In this case thermal expantion will go uncontrolled and will start putting strain on the tank walls and plumbing fixtures.



Electric_Light said:


> Code thing aside, is there a practical reason not to do so?


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## Driftwood (Feb 15, 2004)

protechplumbing said:


> Yes. The further the tank is from the cold inlet of the heater the better. Colder water is kinder to the bladder inside the ex-tank. Some codes do not allow the tank to be seperated from the heater by a valve. Check 1st. I personally don't have a problem installing the tank before the cold water shut off valve provided that there is a backup thermal expansion valve that can't be isolated from the tank but I digress.....
> 
> If you put the ex-tank right on top of the heater it won't last as lond due to heating from convection. Not the end of the world though.
> 
> I highly recomed that you install a pressure relief valve as well as a thermal expansion tank. Set the relief valve a few pounds higher than your static pressure and pipe the relief valve drain to a visible location. If you ever see the relief valve dripping, you know your thermal expansion tank is bad and needs to be replaced. If you don't have said valve installed, you won't know when the bladder goes out. In this case thermal expantion will go uncontrolled and will start putting strain on the tank walls and plumbing fixtures.


 What water Heater WOULDN'T have a T+P ?


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## protechplumbing (Oct 10, 2008)

There was no mention of a T/P valve in my post anywhere. Aperently you don't understand the defference between a T/P valve and a thermal expansion valve. 



Driftwood said:


> What water Heater WOULDN'T have a T+P ?


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## Driftwood (Feb 15, 2004)

protechplumbing said:


> There was no mention of a T/P valve in my post anywhere. Aperently you don't understand the defference between a T/P valve and a thermal expansion valve.


 Expansion tank is for thermal expansion! aperently is spelled apparantly
defference is spelled difference. Let Me Know if You need any more help.


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## Electric_Light (Nov 25, 2007)

I don't know why you'd ever install an expansion tank upstream of shut off valve. It will make it very maintenance unfriendly. I didn't have an expansion tank before, but I added one to eliminate regular spitting from the T&P, as well as pressure on anything connected downstream, particularly the washer hose. 

If the hose is frequently subjected to 150 psi, it may become damaged and burst... and if it does, a ton of water damage.


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## protechplumbing (Oct 10, 2008)

I didn't ask for any. Too bad that in you spell checking you failed to understand what I was trying to explain.



Driftwood said:


> Expansion tank is for thermal expansion! aperently is spelled apparantly
> defference is spelled difference. Let Me Know if You need any more help.


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## KillerToiletSpider (May 27, 2007)

protechplumbing said:


> I didn't ask for any. Too bad that in you spell checking you failed to understand what I was trying to explain.


Drift is a Cali. GC that thinks because his states screwed up code allows him to perform plumbing work that he is in fact a plumber and not just another GC, he has probably never seen a pressure relief valve.

But he will tell you he knows all there is to know to perform plumbing work.


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## Electric_Light (Nov 25, 2007)

KillerToiletSpider said:


> Drift is a Cali. GC that thinks *because his states screwed up code allows him to perform plumbing work that he is in fact a plumber and not just another GC*, he has probably never seen a pressure relief valve.
> 
> But he will tell you he knows all there is to know to perform plumbing work.


So, if he is legally qualified to do plumbing in his jurisdiction, what makes him not a plumber?


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## Mike's Plumbing (Jul 19, 2010)

:laughing: Well....I can legally install cabinets but trust me......you don't want me to unless you don't mind me doing it with a sawzall.:laughing:

It's easy to change out a toilet or a T&P and think your a plumber. The reality is that's not real plumbing.

The home owner type stuff accounts for about 2% of what we learn in our trade. Spend a few hours taking a real plumbing exam and let me know the test score.
----------------------

True story:

I was taking my masters test and an engineer sat next to me. In Wisconsin if you have an engineering degree you can write for your masters and become a plumber. Anyhow, I asked the guy how he thinks he will do on the test and he replied with a very arrogant manor and acted like he was Gods gift.

It's an 8 hour gig and about 30 minutes into it he packed his stuff up and quite. Your not allowed to talk during the test so I just looked at him and smiled. He looked back at me and said "Fu## you!" and walked out of the room.

As plumbers we spend years learning on the job and in the classroom. You can't wing it and be a plumber...it's impossible.

Mike


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## Tinstaafl (Jan 6, 2008)

Electric_Light said:


> So, if he is legally qualified to do plumbing in his jurisdiction, what makes him not a plumber?


I'm legally qualified to do plumbing here (and I do), but I'm not a plumber. I'm legally qualified to do electrical work here (and I do), but I'm not an electrician.

While I instinctively bristle at the apparent snobbishness/arrogance of those who are licensed in such trades where licensing is required, the fact is that as specialists who have had to study, serve apprenticeships and pass rigorous exams, they are just about guaranteed to know more about their specialty than I do as a "casual expert."

OTOH, I get my jollies by knowing that I can build a code-compliant house start to finish just with what's in my head, and most of them can't. :thumbsup:


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## Mike's Plumbing (Jul 19, 2010)

Tinstaafl said:


> I'm legally qualified to do plumbing here (and I do), but I'm not a plumber. I'm legally qualified to do electrical work here (and I do), but I'm not an electrician.
> 
> While I instinctively bristle at the apparent snobbishness/arrogance of those who are licensed in such trades where licensing is required, the fact is that as specialists who have had to study, serve apprenticeships and pass rigorous exams, they are just about guaranteed to know more about their specialty than I do as a "casual expert."
> 
> OTOH, I get my jollies by knowing that I can build a code-compliant house start to finish just with what's in my head, and most of them can't. :thumbsup:


Pfst!.......What....EVER!!!!:laughing:


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## Mike's Plumbing (Jul 19, 2010)

And just think, if Tinstaf tried this in Wisconsin they would lock him up and take away every license he has for the rest of his life.

Were a tough group in cheeseland. Don't mess with us!:laughing:


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## Electric_Light (Nov 25, 2007)

Being 100% code compliant is like, going no more than 50mph on 55mph posted road, because the speed sign is the maximum permissible speed, so you factor in some factor of safety and you'll find yourself at 50mph...


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## Tinstaafl (Jan 6, 2008)

Mike's Plumbing said:


> And just think, if Tinstaf tried this in Wisconsin they would lock him up and take away every license he has for the rest of his life.


No worries. I have no licenses. :smartass:

And in this economy, three hots and a cot is starting to look good. :laughing:


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## Mike's Plumbing (Jul 19, 2010)

Tinstaafl said:


> No worries. I have no licenses. :smartass:
> 
> And in this economy, three hots and a cot is starting to look good. :laughing:


Isn't that the truth though? I have a license and it can be taken away. They guys that don't have nothing to worry about......how does that work?:laughing:

Ahhh, just yanking your chain a little.:clap:

I'm sure your a hack like the next guy.:laughing:

Mike


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## Driftwood (Feb 15, 2004)

*Be nice honey*



KillerToiletSpider said:


> Drift is a Cali. GC that thinks because his states screwed up code allows him to perform plumbing work that he is in fact a plumber and not just another GC, he has probably never seen a pressure relief valve.
> 
> But he will tell you he knows all there is to know to perform plumbing work.


 :whistlingI'm also a Cert . welder. this is My 48 th year in the trades.
former Sgt USMC wish You were a little closer Honey ! I'd love to buy You a 
a milk shake. Yes I am licensed to do it all in Ca., and I do. Now " SUCK IT UP, BUTTERCUP "


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