# Thermal Expansion Tank Maintenance



## plumberkc (Jun 23, 2011)

Amtrol Expansion tank Manual 

“A professional plumber should check the complete system, including the expansion tank, yearly and more frequently as the system ages. Checking the precharge allows a small quantity of air to escape and can result in an insufficient air charge. Always check the precharge while the tank is isolated and empty of water, and be sure to maintain the proper precharge whenever the tank is inspected.”

Do you guys warranty the expansion tanks along with the water heaters you install? I figure that a maintenance plan to inspect yearly would cost more than $2,000 over the life of a water heater. 

As soon as I startup a water heater I'll have the pressure gauge hooked up and watch to see if the water pressure rises. Less than 20% of the water heaters that I install actually have a rise in water pressure while the gauge is hooked up.


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## PLUMBER_BILL (Oct 23, 2009)

plumberkc said:


> Amtrol Expansion tank Manual <snip>
> 
> When making a service it was always mandatory, that the water is shut off at the main valve. Then go to a cold water faucet, if the water does not run from that faucet for a period of [lets say] 15 seconds. You can almost be sure that the therm tank is faulty. A good thermal tank will continue to push water under pressure. Of course that after you have shut the main it's possible that a faucet was in use, toilet flushed --- what not. But it is a good guide on service try it out!


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## KoleckeINC (Oct 22, 2011)

Manufacturers warranty on it. Tap it with something high pitch-full of air-good! Low pitch-waterlogged bad.


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## Bpo1222 (Nov 24, 2010)

All thermal expansion tanks should be charged to the house pressure after the reducing valve. Failure to do this will result in premature failure of the tank. Also the expansion tank is pretty useless. Most tanks come precharged to 30psi.


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## sparky (Jan 8, 2014)

Bpo1222 said:


> All thermal expansion tanks should be charged to the house pressure after the reducing valve. Failure to do this will result in premature failure of the tank. Also the expansion tank is pretty useless. Most tanks come precharged to 30psi.


I just charge expansion tanks to 70-75psi ever time,no matter what the incoming pressure is,80 psi is max anyways


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## plumberkc (Jun 23, 2011)

sparky said:


> I just charge expansion tanks to 70-75psi ever time,no matter what the incoming pressure is,80 psi is max anyways


 I check pressure in every house and it's fairly common to have water pressure exceed 80 psi.


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## wyrickmech (Mar 16, 2013)

plumberkc said:


> I check pressure in every house and it's fairly common to have water pressure exceed 80 psi.


 and also against code.


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## Plumber patt (Jan 26, 2011)

Expansion tanks should be charged 20-30% less than incoming pressure. If you have it charged to the same pressure where is the thermal EXPANSION going to expand too? There is a reason they are sometimes called cushion tanks...

And if you suspect your tank is water logged just tap the shraeder valve for a second, if water comes out, tank is pooched...


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## plumberkc (Jun 23, 2011)

wyrickmech said:


> and also against code.


I would be fine with 84psi at any one of my rentals.


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## plumberkc (Jun 23, 2011)

Plumber patt said:


> Expansion tanks should be charged 20-30% less than incoming pressure. If you have it charged to the same pressure where is the thermal EXPANSION going to expand too? There is a reason they are sometimes called cushion tanks... And if you suspect your tank is water logged just tap the shraeder valve for a second, if water comes out, tank is pooched...


An expansion tank is steel with no glass liner. Inflate it below the water pressure and it will look like this in less than 2 years.


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## Bpo1222 (Nov 24, 2010)

Actually when water is heated it expands.... So if you have 50psi in the house and your heater heats up and the pressure rises above 50psi (inevitably this will happen) it will expand into the tank. Thus doing its job. Now if your tank is under charged then it will have no where to expand to. This is because if you have 50psi in the home and 30psi in your tank the rubber bladder will be forced against the steel tank wall leaving no area for expansion. I usually charge my tanks to 2psi above incomming pressure. Just like a well storage tank. This will allow the water to get pushed back out of tank when heating process is complete.


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## Master Mark (Aug 14, 2009)

They are a joke because I dont think half of them last the
life of the warranty on the heater... and who wants the plumber to come out and have to pay them to service them every year??? The 5 gallon ones are ok and have a chance of working for a while, but the smaller ones wont last a year

We can have this debate again if everyone wants to... if the incoming water pressure is at 70 psi, I set the air in the expansion tank at 75+...

What good is a pressure tank if it is set below or at even and basically already full of water and maxed out from the start??


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## wookie (Dec 16, 2008)

Expansion tanks should last the life of the heater some don't... why???

I have quite a few reverse osmosis customers The storage tanks for the most part easily last 10 plus years. Is it because its treated water and expansion tank is not. Pressures not the same in RO. I believe they are constructed the same ????

Would a nitrogen filled hammer arrestor type expansion chamber work better? Probably way to expensive to manufacture. If they won't make a good expansion now because of cost they sure won't go nitrogen.


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## plumberkc (Jun 23, 2011)

Master Mark said:


> They are a joke because I dont think half of them last the life of the warranty on the heater... and who wants the plumber to come out and have to pay them to service them every year??? The 5 gallon ones are ok and have a chance of working for a while, but the smaller ones wont last a year We can have this debate again if everyone wants to... if the incoming water pressure is at 70 psi, I set the air in the expansion tank at 75+... What good is a pressure tank if it is set below or at even and basically already full of water and maxed out from the start??


It's almost like we do these everyday.


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## Master Mark (Aug 14, 2009)

plumberkc said:


> It's almost like we do these everyday.


Yea, its like we do this for a living or something duuuua:laughing:


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## Plumber patt (Jan 26, 2011)

This place is so back asswards sometimes


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## plumberkc (Jun 23, 2011)

Plumber patt said:


> This place is so back asswards sometimes


 Maybe you should go back and look at some of the installations that you did three years ago. I guarantee they have about a 90% fail rate.


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## wharfrat (Nov 1, 2014)

Rarely see expansion tanks out here. Sometimes on commercial systems.


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## Plumber patt (Jan 26, 2011)

plumberkc said:


> Maybe you should go back and look at some of the installations that you did three years ago. I guarantee they have about a 90% fail rate.


I check every expansion tank I've put in every year when testing the backflows. They are all fine.


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## Master Mark (Aug 14, 2009)

plumberkc said:


> Maybe you should go back and look at some of the installations that you did three years ago. I guarantee they have about a 90% fail rate.



I know that his is probably a very stupid question but it makes me wonder about the quality of a water heater expansion tank... 

Can they be so cheaply made that the heat from the water heater literally destroys them over time or could it be the distance and placement on the cold line away from the heater and the heat or constant expansion and contraction?? 

Or is it simply the pressure you have to pump them up to ??

I just buy whatever my salesman has in stock but are their better quality brands on the market I dont know about???


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## CTs2p2 (Dec 6, 2011)

The quality of the water itself and the mineral content would most likely be the biggest variable as far as how long both the heater and the xtank will last..

2psi above incoming is what I precharge mine to, I believe manufactures spec is to match incoming psi


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## Master Mark (Aug 14, 2009)

CTs2p2 said:


> The quality of the water itself and the mineral content would most likely be the biggest variable as far as how long both the heater and the xtank will last..
> 
> 2psi above incoming is what I precharge mine to, I believe manufactures spec is to match incoming psi



Water quality, aggressive water... I forgot about that


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## plumberkc (Jun 23, 2011)

Plumber patt said:


> I check every expansion tank I've put in every year when testing the backflows. They are all fine.


Do you install di-electric unions to join the dissimilar metals?


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## wookie (Dec 16, 2008)

plumberkc said:


> Do you install di-electric unions to join the dissimilar metals?


Thats the biggest beef I have with Bradford White. Let me install brass nipples and make a stand alone anode rod. 

BW is all I install unless customer has another sitting there. 

I can't say with 100% conviction that BW is a better product. Have had no issues just wish I could tell customer oh yeah BW is a way better product than ........

Tank construction is mainly what I'm referring to. Can anyone educate me?

Made in USA is not enough IMHO


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## Nathan901 (Feb 11, 2012)

I was told rheem buys all their smaller tank from Bradford. 
According to the same source the only tanks rheem is producing is the larger boiler tanks.


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## plumberkc (Jun 23, 2011)

Nathan901 said:


> I was told rheem buys all their smaller tank from Bradford. According to the same source the only tanks rheem is producing is the larger boiler tanks.


 So BW is supplying HD? Where did you hear that?


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## Nathan901 (Feb 11, 2012)

If i remember correctly it was a supply house counter guy. Hard to believe but he seemed pretty sure.


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