# Water heater expansion tank



## HomerJ (Jan 23, 2009)

Is it necessary for a new GE 50 gal 12 yr tank?


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## KillerToiletSpider (May 27, 2007)

What does your local code specify?


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## Ron The Plumber (Oct 10, 2006)

HomerJ said:


> Is it necessary for a new GE 50 gal 12 yr tank?


What are you asking? Please rephrase it so it is understandable.


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## Ron The Plumber (Oct 10, 2006)

Never mind my question see KTS's response.


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## naptown CR (Feb 20, 2009)

Ron The Plumber said:


> What are you asking? Please rephrase it so it is understandable.


What part didn't you understand?
He is asking if an expansion tank is required for an brand new 50 gallon Ge water heater with a 12 year warranty.

The answer depends on the local code.
If on a water system there is no backflow preventer it is not required unless by code or to satisify the warranty.


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## Ron The Plumber (Oct 10, 2006)

naptown CR said:


> What part didn't you understand?
> He is asking if an expansion tank is required for an brand new 50 gallon Ge water heater with a 12 year warranty.
> 
> The answer depends on the local code.
> If on a water system there is no backflow preventer it is not required unless by code or to satisify the warranty.


Thanks I figured it out.


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## Ron The Plumber (Oct 10, 2006)

HomerJ said:


> Is it necessary for a new GE 50 gal 12 yr tank?



What is the residual and static pressure at?


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## HomerJ (Jan 23, 2009)

I'll have to check the local code.

According to the plumber, there is a backflow preventer.


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## vinpadalino (Dec 17, 2009)

If you have a well I would say no. If you have city water I would say yes to be on the safe side. depends on the psi coming from the street side though.


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## KillerToiletSpider (May 27, 2007)

vinpadalino said:


> If you have a well I would say no. If you have city water I would say yes to be on the safe side. depends on the psi coming from the street side though.


No, not really.

In fact you are completely wrong.


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## naptown CR (Feb 20, 2009)

Please explain/\


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## vinpadalino (Dec 17, 2009)

KillerToiletSpider said:


> No, not really.
> 
> In fact you are completely wrong.


No I'm right. If you have a well tank the water will expand inside of the bladder. If you have a bladder type tank only. If you have city water and if the city water exceeds 150 psi were does the water expand to. It doesn't it will trip your relief valve on the water heater. :notworthy


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## KillerToiletSpider (May 27, 2007)

vinpadalino said:


> No I'm right. If you have a well tank the water will expand inside of the bladder. If you have a bladder type tank only. If you have city water and if the city water exceeds 150 psi were does the water expand to. It doesn't it will trip your relief valve on the water heater. :notworthy


If the city water exceeds 150 PSI the relief valve is going to pop anyway, and I have seen plenty of well systems that would not allow expansion to make it to the tank.


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## vinpadalino (Dec 17, 2009)

KillerToiletSpider said:


> If the city water exceeds 150 PSI the relief valve is going to pop anyway, and I have seen plenty of well systems that would not allow expansion to make it to the tank.


 :whistling
No disrespect. You need a pressure reducing valve on water that comes from the city in most cases. thats plumbing 101.
A pressure relief valve on a water heater is set 150psi and the temperature is 210 degrees or around there. If you have a well pump the max psi would be 60-70 if set up for a standard residential home and thats on the high side. When the water heats up it will expand back into the well tank. 
There is no real difference between a well tank and a expansion tank. :whistling


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## beenthere (Mar 5, 2009)

In most of the areas I work.
Both well and city water systems require an expansion tank.

Well systems: To prevent hot water from being pushed into the well tank, and the cold water lines feeding the rest of the home.
City systems: Prevent it from being pushed into the city pipe, and into the cold water lines feeding the rest of the home.

I look at it 2 ways:

1. More money for me.
2. Helps prevents tank rupture (liner fatigue) from sudden pressure shock when faucets are suddenly slammed shut. By appliances like clothes and dishwashers.


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## KillerToiletSpider (May 27, 2007)

vinpadalino said:


> :whistling
> No disrespect. You need a pressure reducing valve on water that comes from the city in most cases. thats plumbing 101.
> A pressure relief valve on a water heater is set 150psi and the temperature is 210 degrees or around there. If you have a well pump the max psi would be 60-70 if set up for a standard residential home and thats on the high side. When the water heats up it will expand back into the well tank.
> There is no real difference between a well tank and a expansion tank. :whistling


There is if the tank is isolated from the rest of the water supply system with a backflow preventer to protect the well from contamination, a very common setup here, and you're the one that started throwing out pressures without adding that a pressure reducing valve also stops the expansion on the cold water side. 

But hey, it's all good, I don't know jack about this plumming crap anyhoo.


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## The Coastal Craftsman (Jun 29, 2009)

vinpadalino said:


> :whistling
> No disrespect. You need a pressure reducing valve on water that comes from the city in most cases. thats plumbing 101.
> A pressure relief valve on a water heater is set 150psi and the temperature is 210 degrees or around there. If you have a well pump the max psi would be 60-70 if set up for a standard residential home and thats on the high side. When the water heats up it will expand back into the well tank.
> There is no real difference between a well tank and a expansion tank. :whistling


They are basicly the same thing but the accumulators for the well water are normally a lot larger.


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## vinpadalino (Dec 17, 2009)

KillerToiletSpider said:


> There is if the tank is isolated from the rest of the water supply system with a backflow preventer to protect the well from contamination, a very common setup here, and you're the one that started throwing out pressures without adding that a pressure reducing valve also stops the expansion on the cold water side.
> 
> But hey, it's all good, I don't know jack about this plumming crap anyhoo.


I guess thats why there different codes for different states. I have city water and normally the water psi is 60. At night when no one is using the water it spikes. If you don't have a pressure reducing valve on the main the psi will top 150 and thats on the cold side. My water heater will blow off on psi because it cant push that 150 psi back into the street. But I have a pressure reducing valve with a built in check valve so I need some where for the expansion to go. 
Again no offense. This is how things are done around here. Plus been there is right more money for us. and some water heaters wont warranty the product if there is no expansion tank, but then again they don't warranty the product if the water is hard lol.:thumbup:


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## 747 (Jan 21, 2005)

I'm on city water. I don't have one on mine. So it definately isn't code where i live. I'm also 99 percent sure no back flow preventer.:laughing: Just two copper pipes out of the wall into it. Then theres a copper pipe running to the hot water boiler sitting next to it. Of course that has a expansion tank on it. I keep that filled with 12 pounds of air.:thumbsup:


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## beenthere (Mar 5, 2009)

747 said:


> I'm on city water. I don't have one on mine. So it definately isn't code where i live. .:thumbsup:


or it wasn't inspected.


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## 747 (Jan 21, 2005)

My home was built back in the early 60's. So it might be grandfathered in. I also live in a small town. I'll ask my plumber.:laughing: He was over a couple weeks ago to put a new coupler on my b&g 100 series circulator pump on the boiler. It runs sweet now. :laughing:


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## akerplmbr (Dec 22, 2009)

I know State & Bradford White units ,manufacturer requires txp tank if a prv is installed,or any kind of check valve or backflow located on main service,if no prv or check valve,one is not required,,but check local codes too,as they vary. the above is from international code.


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## UALocal1Plumber (Jun 19, 2009)

naptown CR said:


> The answer depends on the local code.
> If on a water system where there is no backflow preventer it is not required unless by code or to satisify the warranty.


I believe this is the most correct answer.

In NYC domestic water heater expansion tanks are necessary only if there is a backflow preventer somewhere on the line, upstream of the DHW heater. This can include an RPZ, DCVA, vacuum breaker or other mechanical appurtenance. 

Obviously if the manufacturer demands a device to be installed in order to satisfy warranty conditions, or to guarantee performance, you should also install it.

NYC Plumbing code:
607.3.1 Pressure-reducing valve. For water service system sizes up to and including 2 inches (51 mm), a device for controlling pressure shall be installed where, because of thermal expansion, the pressure on the downstream side of a pressure-reducing valve exceeds the pressure-reducing valve setting.
607.3.2 Backflow prevention device or check valve. Where a backflow prevention device, check valve or other device is installed on a water supply system utilizing storage water heating equipment such that thermal expansion causes an increase in pressure, a device for controlling pressure shall be installed.

Keith


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## ARealplumber (Aug 11, 2009)

In a closed system thermal expansion must be controlled. There are a few ways a system can be closed without a backflow device. Its not as likely but still possible.


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## jeffreyplumber (Jan 11, 2010)

*thank you your right on!!*



UALocal1Plumber said:


> I believe this is the most correct answer.
> 
> In NYC domestic water heater expansion tanks are necessary only if there is a backflow preventer somewhere on the line, upstream of the DHW heater. This can include an RPZ, DCVA, vacuum breaker or other mechanical appurtenance.
> 
> ...


 In Ca we have upc code and although I find many differances around the country, This is basicly the same as our code. It protects the system against excesive pressure, caused by the heating of water. 

Of cource there are house all over without one. As there are people that drive there car without a seat belt. Its perfectly legal as long as a cop dont see you. Dont go by what your 50 year old house has on it! My 1958 chevy doesent have a catalytic converter, so my 2009 ford doesent need one either>


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## radimeto (Jan 14, 2010)

HomerJ said:


> Is it necessary for a new GE 50 gal 12 yr tank?


 Depend on your local plumbing code .
But is good to have it , will protect the water heater and the plumbing system
if you don't have it, your pressure will rise up to 110 pound ,when the water heater start recover the hot water. you can make the test


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## TravelTradesman (Jan 28, 2010)

HomerJ said:


> Is it necessary for a new GE 50 gal 12 yr tank?


Only if there is a check valve or a rpz on the main water feed to the house. If there is no check = you need no tank.


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## Plumbermurrieta (Feb 21, 2010)

The GE tankless gas water heater provides a continuous flow of precisely heated hot water.* There's no tank, so it can't run empty. And the water stays hot until you turn it off.


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## M5Plumb (Oct 31, 2009)

Thank you! That is the right answer. Check for a closed loop system. Things to remember, and this mostly applies to a gas fired W/H. 
1. Do a closed loop test on the system, if pressure goes up, you need an Exp Tk.
2. If the pressure remains static around 60 - 70 you are fine.
3. Some codes require it regardless of PRV or DCVA
4. Even with recirc systems, a closed loop can still be a problem.

:clap:



ARealplumber said:


> In a closed system thermal expansion must be controlled. There are a few ways a system can be closed without a backflow device. Its not as likely but still possible.


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## DavidC (Feb 16, 2008)

I don't recall ever seeing an expansion tank on a hot water heater, city or well systems. It doesn't sound like it could hurt even if not required, but I doubt I would do at home.

Good Luck
Dave


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## UALocal1Plumber (Jun 19, 2009)

Of course it can hurt if not required. It's money wasted if there's no DCVA. It's like putting a seatbelt on while parked in your driveway. Why the hell would you do it?

Keith


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## beenthere (Mar 5, 2009)

UALocal1Plumber said:


> Of course it can hurt if not required. It's money wasted if there's no DCVA. It's like putting a seatbelt on while parked in your driveway. Why the hell would you do it?
> 
> Keith


Guess that means its a waste of money to have seat belts for 4 people in a car. That never has more then 1 occupant in it.


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## DavidC (Feb 16, 2008)

UALocal1Plumber said:


> Of course it can hurt if not required. It's money wasted if there's no DCVA. It's like putting a seatbelt on while parked in your driveway. Why the hell would you do it?
> 
> Keith


Well, if a client wanted one even after I said it wouldn't do anything for his system, I would install it and make a profit. Then it would be doing some good.

Good Luck
Dave


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## UALocal1Plumber (Jun 19, 2009)

Of course. . . the customer's needs and wishes are paramount. If the lady wants a toilet in the living room, that's what you give her, and charge for it. 

But to install the XTank in a situation where it has no purpose is retarded. May as well polish the pipe to make the water flow better. No purpose.

Keith


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## beenthere (Mar 5, 2009)

Helps get a longer life span for the tanks by protecting the liner from shock from the pressure surge when faucets are quickly closed.


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