# Expansion Tank or Thermal expansion bypass valve



## Plumbergeek (Aug 16, 2010)

Expansion Tank or Thermal expansion bypass valve?

Customer is replacing (2) 80 gallon electric water heaters and he would rather not use expansion tanks due to previous tank failures, I suggested the bypass valve & pipe discharge to outside. http://www.supplyhouse.com/Watts-0371271-1-2-530C-Poppet-Style-Relief-Valve-3569000-p?gclid=Cj0KCQjwm9vPBRCQARIsABAIQYebvu0zt910gG4-vpZhZ3k7mxFLnv97RywPy1619pwvRBX6pbA1o3gaAgg-EALw_wcB
Any pro or cons or suggestions?


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## Master Mark (Aug 14, 2009)

Their are some cheap ass plumbers in town that have used a ball valve to the water heaters with a built in expansion valve on the stop... you have to run a weep drain down to the floor drain

I assume that they work... I try to never touch them when I change out a heater because they can be fussey... i guess they work but I would rather have the expansoin tanks on the heaters .


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## Plumbergeek (Aug 16, 2010)

Thanks Mark! 
Maybe that's why I never see any here, I didn't know they were temperamental.
I will just use the tanks on this job and explain to him that they are the best option.


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## MACPLUMB777 (Jun 18, 2008)

The poppet valve is not for Thermal Expansion, and not for Potable Water use !

The valve that Mark posted on I saw a lot of in SLC, UT 10 years ago used 
on all new construction but they waste water, Water that you you just paid money to heat is going down the drain


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## OpenSights (Mar 23, 2015)

It’s pretty rare you see an expansion tank on a heater, I see them once or twice a year at the most. Boilers, all the time. I know what they’re for, but other than that I know very little about them, so it’s always a treat reading about them.


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## 5onthefloor (Sep 13, 2017)

OpenSights said:


> It’s pretty rare you see an expansion tank on a heater, I see them once or twice a year at the most. Boilers, all the time. I know what they’re for, but other than that I know very little about them, so it’s always a treat reading about them.


I have taken pressure readings on a hose bibb and have seen pressure spike 10+psi if the water heater is on and there is no expansion tank. 
What gets me is when guys install them with just precharge air or install them horizontally with no bracing or support. You're just asking for a problem

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## OpenSights (Mar 23, 2015)

I haven’t had to deal with high water pressure since I moved to Michigan, here our battle is with low pressure do to old galvanized or water quality and built up sediment. Smaller communities like mine use water towers, once on each side of the bridge. Not really sure how Lansing regulates their pressure, but I’ve never felt anything thing alarming. Mater of fact, I haven’t seen my gauge in 14 years...


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## Plumbergeek (Aug 16, 2010)

We always support them around here....... Lean them on the hot pipe and they are good to go!


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## 5onthefloor (Sep 13, 2017)

Plumbergeek said:


> We always support them around here....... Lean them on the hot pipe and they are good to go!


Dammmm sun!

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## Plumbergeek (Aug 16, 2010)

5onthefloor said:


> Dammmm sun!
> 
> Sent from my SM-G930V using Tapatalk


I have lots more.


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## OpenSights (Mar 23, 2015)

It would still be scary with copper!


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## OpenSights (Mar 23, 2015)

3”. Ilegal vent here. Kinda sorta.....


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## 5onthefloor (Sep 13, 2017)

OpenSights said:


> 3”. Ilegal vent here. Kinda sorta.....


Why?

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## OpenSights (Mar 23, 2015)

5onthefloor said:


> Why?
> 
> Sent from my SM-G930V using Tapatalk


Heartens are more efficient and give out more moisture destroying the brick and morter.


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## OpenSights (Mar 23, 2015)

Oh, 3”, just because. Extra re-inspection fee.


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## OpenSights (Mar 23, 2015)

Once I tossed a 3” vent and up graded to 4” vent wasn’t good enough. Had to buy new. Had to drop to 3”. 

Our inspectors have no clue! Scary!


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## rwh (Dec 17, 2014)

We use those reliefs on fire pumps. Allows for churning without deadheading.


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## GAN (Jul 10, 2012)

Around my area water purveyors are putting checks on the meter yokes for protection. So a lot of expansions tank are going in.
Existing homes when the meter is upgrades they will let you put in the ballcock expansion relief.

The vent would be whatever the manufactures calls for. I hate to see the upgrades with WH venting still ran to a brick chimney. Not good. Can cause the CO to fall back into the home as well as water damage. You loose the heat & velocity you can have issues. Not always as simple as hooking it back up. Two story structures may be running 3" all the way instead of 4".


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## MACPLUMB777 (Jun 18, 2008)

Plumbergeek said:


> I have lots more.


What happens to that CPVC piping when that Expansion tank 
gets water logged ?


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## OpenSights (Mar 23, 2015)

MACPLUMB777 said:


> What happens to that CPVC piping when that Expansion tank
> gets water logged ?


Insurance claim. Biggest scam ever invented.


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## Plumbergeek (Aug 16, 2010)

MACPLUMB777 said:


> What happens to that CPVC piping when that Expansion tank
> gets water logged ?


Both pictures I posted had water logged tanks, the homeowners were very lucky they didn't break.....


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## rwh (Dec 17, 2014)

MACPLUMB777 said:


> Plumbergeek said:
> 
> 
> > I have lots more.
> ...




"I'm glad to see they used cpvc" ????. To whichever dip shut was arguing the virtues of cpvc with me the other day, yes, it is for hacks.


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## Plumbergeek (Aug 16, 2010)

rwh said:


> "I'm glad to see they used cpvc" ????. To whichever dip shut was arguing the virtues of cpvc with me the other day, yes, it is for hacks.


 I hate CPVC ! Unfortunately it's in 90% of the homes around me.


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## Gargalaxy (Aug 14, 2013)

No comments..... :laughing:


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## 5onthefloor (Sep 13, 2017)

Gargalaxy said:


> No comments..... :laughing:


..









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## Plumbergeek (Aug 16, 2010)

I almost forgot this one, it's a classic :laughing::laughing:


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## 5onthefloor (Sep 13, 2017)

Plumbergeek said:


> I almost forgot this one, it's a classic :laughing::laughing:


What no points for strapping that tank?!

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## Gargalaxy (Aug 14, 2013)

Plumbergeek said:


> I almost forgot this one, it's a classic :laughing::laughing:


At least not bongee cords :laughing: but they spend more in SB than the water heater itself.


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## PLUMBER_BILL (Oct 23, 2009)

5onthefloor said:


> I have taken pressure readings on a hose bibb and have seen pressure spike 10+psi if the water heater is on and there is no expansion tank.
> What gets me is when guys install them with just precharge air or install them horizontally with no bracing or support. You're just asking for a problem
> <snip>
> 
> Some previous talk on therm tanks ... Go into tag search in the dialog box type SUPPORT open the one that contains BRA


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