# Cracked expansion tank



## Pacificpipes (Oct 1, 2013)

I've honestly never seen one fail. 1st for me.


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## Burner tech (Oct 24, 2013)

I've see it happen before but not often.


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## wookie (Dec 16, 2008)

Had an RO storage tank blow. Not as messy as an expansion tank, but shook up the customer.


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## rjbphd (Feb 5, 2010)

Pacificpipes said:


> I've honestly never seen one fail. 1st for me.


 Made by X-trol ?? Expect that, metal from china.. I refuse to install well x trol tank..


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## BC73RS (Jan 25, 2014)

Hmm never seen that, anybody know what the pressure could have been when it popped and why?


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## Pacificpipes (Oct 1, 2013)

I'll check. I saved the tank. Pressure in the house was 60psi.


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## rjbphd (Feb 5, 2010)

Pacificpipes said:


> I'll check. I saved the tank. Pressure in the house was 60psi.


Not sure or checked.. I think they have pressure rating up to 75 cold psi..


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## redbeardplumber (Dec 4, 2012)

rjbphd said:


> Not sure or checked.. I think they have pressure rating up to 75 cold psi..


Nah..., isn't it 150 psi


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## BC73RS (Jan 25, 2014)

150 hmm, max. working pressure? Thinking higher than that.


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## Pacificpipes (Oct 1, 2013)

I was going to check the brand. The pressure was the first thing I checked. It's a Water-guard made by state industries


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## rjbphd (Feb 5, 2010)

BC73RS said:


> 150 hmm, max. working pressure? Thinking higher than that.


Sh!t... well pressure tank are rated 75 psi and required a relief valve.. while these smaller bomb don't??


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## BC73RS (Jan 25, 2014)

rjbphd said:


> Sh!t... well pressure tank are rated 75 psi and required a relief valve.. while these smaller bomb don't??


That's what I thought too, why didn't the safety device not blow first, still doesn't answer the question of why though.


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## Burner tech (Oct 24, 2013)

rjbphd said:


> Sh!t... well pressure tank are rated 75 psi and required a relief valve.. while these smaller bomb don't??


 I'm not sure how the small ones are built. But the larger expansion tanks are a bladder that the water goes into, so the water never comes into contact with the actual walls of the tank unless there is a bladder failure. A relief valve on an expansion tank would be pointless as it is designed to absorb thermal expansion. If I'm not mistaken a well tank is designed to pressurize, and hold said pressure so the wells pump does not need to run constantly. My knowledge of well tanks is minimal so please correct me if I am wrong. 
*edit*
I was just thinking about it and a well tank is built the same way, correct? I would assume it is just due to the application. As a well tank could be constantly pressurized from faulted pressure switch not allowing the pump to shut off.


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## Pacificpipes (Oct 1, 2013)

I'm guessing bladder failure caused rust to break it. The guy was on his way to see Godzilla. He was just excited I could replace it so fast.


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## wyrickmech (Mar 16, 2013)

Had one fail the other day. The man had set the tank next to the brine tank and it had leaked. When it went it destroyed all the connecting pipes.


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## Dpeckplb (Sep 20, 2013)

Burner tech said:


> I'm not sure how the small ones are built. But the larger expansion tanks are a bladder that the water goes into, so the water never comes into contact with the actual walls of the tank unless there is a bladder failure. A relief valve on an expansion tank would be pointless as it is designed to absorb thermal expansion. If I'm not mistaken a well tank is designed to pressurize, and hold said pressure so the wells pump does not need to run constantly. My knowledge of well tanks is minimal so please correct me if I am wrong.
> *edit*
> I was just thinking about it and a well tank is built the same way, correct? I would assume it is just due to the application. As a well tank could be constantly pressurized from faulted pressure switch not allowing the pump to shut off.


Well pressure tanks have a Bladder that has air pressure in it. Newer ones anyways.


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## Burner tech (Oct 24, 2013)

http://www.cyclestopvalves.com/csvbasicinfo_19.html

http://www.apswater.com/article.asp...s+and+how+to+use+it+for+low+pressure+problems

http://www.watts.com/pages/learnabout/thermalExpansion.asp

All this talk got me more interested in the how and whys of expansion and well tanks.


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## budders (May 19, 2013)

Ive seen 3 in the past year fail all amtrol one on a res oil fired boiler and 2 on comerical gas fired boilers.


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## rjbphd (Feb 5, 2010)

budders said:


> Ive seen 3 in the past year fail all amtrol one on a res oil fired boiler and 2 on comerical gas fired boilers.


The tank alone failed or the bladder?? Was told to use potable exp tank over hydronic tank for heating as the rubber is suppose to be better.


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## budders (May 19, 2013)

The metAl wall develops pin holes. The 2 commercial ones misted like a spider webb and the res developed a rust bubble under the paint and a rusty stream down the side of the tank i changed it out. When i drained the old one i could flex the wall with my thumb


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## rjbphd (Feb 5, 2010)

budders said:


> The metAl wall develops pin holes. The 2 commercial ones misted like a spider webb and the res developed a rust bubble under the paint and a rusty stream down the side of the tank i changed it out. When i drained the old one i could flex the wall with my thumb


All made by Scamtrol??


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## budders (May 19, 2013)

Yep


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## rjbphd (Feb 5, 2010)

budders said:


> Yep


I try to avoid them whenver I can.. think the last well x trol tank I installed was over 20 years ago... never again, of what they did to plumbers and the damages they did to customer's homes.. do any of you recall what they did?? Think Ford Pinto cars...


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## Dpeckplb (Sep 20, 2013)

I just thought of this but this week has been nuts with expansion and pressure tanks failing. I changed 6 expansion tanks and 4 pressure tanks in two days. It was just a fluke I'm sure.


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## Pipemaster41 (Jan 9, 2011)

I know some of those tanks are rated for cold water only. Was it put on hot water side?


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## rjbphd (Feb 5, 2010)

Pipemaster41 said:


> I know some of those tanks are rated for cold water only. Was it put on hot water side?


 Pipemaster, which side is the exp tank suppose to be?


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## Pipemaster41 (Jan 9, 2011)

Most of them are rated for cold water only. For domestic water expansion tanks


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## rjbphd (Feb 5, 2010)

Pipemaster41 said:


> Most of them are rated for cold water only. For domestic water expansion tanks


 What about for the hydronic heating system?


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## Pipemaster41 (Jan 9, 2011)

they are designed to be used for the heating system, but they cost a lot more


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## rjbphd (Feb 5, 2010)

Pipemaster41 said:


> they are designed to be used for the heating system, but they cost a lot more


So, tell us how they designed for heating system, ? Pressure, volume,Boyle's law, cold water temps inlet?


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## rjbphd (Feb 5, 2010)

rjbphd said:


> So, tell us how they designed for heating system, ? Pressure, volume,Boyle's law, cold water temps inlet?


Why do they costs more?


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## Pipemaster41 (Jan 9, 2011)

I never actually read the instructions, but I know the ones made for domestic water and the ones made for heat are different.


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## Pipemaster41 (Jan 9, 2011)

If you go to Watts homepage, there are spec sheets there that explain the difference between the tanks designed for potable and non potable water


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