# Water heater expansion tanks



## pauliplumber

In MA expansion tanks on water heaters are not required by code. I can't ever remember seeing one installed on a WH. I can see from most of the pictures on here that it's code in most (if not all) of the rest of the country. Yet in MA it IS code to install a vac relief on all water heaters.

How important do you think it is for a expansion tank to be installed on a water heater?
How important do you think it is to install a vac relief on a water heater?


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## ILPlumber

I think they both are important. 

Both are required in IL under certain circumstances.

If you have checks in the water meter. The expansion tank is a must. Due to the fact you have created a closed system.

Some guys use those governor ball cocks to relieve the pressure created by expansion. I don't agree with this practice.

Vac relief will prevent the water heater from siphoning dry if the system is off and drained or if there is back siphonage.


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## service guy

ILPlumber said:


> I
> If you have checks in the water meter. The expansion tank is a must. Due to the fact you have created a closed system.


Exactly. Its really quite simple. Maybe in Mass there are no checks on the meters, but here they are putting them in all the new meters, and slowly updating them. I can always tell when someone's water meter just got updated as the T&P starts dripping and they have no TXT installed. The only place I don't install them is on a well tank, as it is already serving as an expansion tank also, as long as there is no check between the water heater and well tank.


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## Master Mark

*A water heater PAN is your best freind......*

if the pressure in the area is not high,
then it is not required here...

*I am a firm believer ina water heater pan, over all else...I have seen enough greif and misery without one.*

I dont care for the expansion tanks becasue no one ever checks them and about 5 years down the road they go bad 
and get waterlogged.....with about 30 lbs of weight hanging 
and wobbling in mid air..

If you are hell bent on a thermal expansin tank you ought to at least put a hanger, or a PVC pipe crutch up to hold the weight instead of letting the copper tee do all the work.....

I used to think that the thermal tank extended the life of the heater, but it just aint so......

I have had thermal expansion tanks get water logged and rust a hole out the side to them and flood the home
before... 

I do offer them for about another 100 bucks,

but a pan is my best buddy, 
I dont hear any **** 
out of anyone 10 years down the road it it starts to leak,
if you saved their carpet and their home with that pan,
then you are their hero not their enemy


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## TheMaster

service guy said:


> Exactly. Its really quite simple. Maybe in Mass there are no checks on the meters, but here they are putting them in all the new meters, and slowly updating them. I can always tell when someone's water meter just got updated as the T&P starts dripping and they have no TXT installed. The only place I don't install them is on a well tank, as it is already serving as an expansion tank also, as long as there is no check between the water heater and well tank.


On a well system i always install a dedicated expansion tank at the water heater. This is just my way and I'm not saying i'm right or wrong. Let me offer you an explaination. There are more ways for a system to become closed other than a check valve and prv's. Someone could close the stop valve at the water heater and leave the heater on. that would close the system then the bladder tank is useless at the well. I've seen it done more than once. For this reason i always install a dedicated thermal expansion tank or other thermal expansion relieving device at the water heater on the heater side of the valve.


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## service guy

True TM, good point. Someone could close a valve to the tank while its heating. But 99% of the time, if a valve is closed for any length of time, the heater will be shut off anyway.


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## TheMaster

Master Mark said:


> if the pressure in the area is not high,
> then it is not required here...
> 
> *I am a firm believer ina water heater pan, over all else...I have seen enough greif and misery without one.*
> 
> I dont care for the expansion tanks becasue no one ever checks them and about 5 years down the road they go bad
> and get waterlogged.....with about 30 lbs of weight hanging
> and wobbling in mid air..
> 
> If you are hell bent on a thermal expansin tank you ought to at least put a hanger, or a PVC pipe crutch up to hold the weight instead of letting the copper tee do all the work.....
> 
> I used to think that the thermal tank extended the life of the heater, but it just aint so......
> 
> I have had thermal expansion tanks get water logged and rust a hole out the side to them and flood the home
> before...
> 
> I do offer them for about another 100 bucks,
> 
> but a pan is my best buddy,
> I dont hear any ****
> out of anyone 10 years down the road it it starts to leak,
> if you saved their carpet and their home with that pan,
> then you are their hero not their enemy


thermal expansion is caused by the water heater itself so the supply pressure shouldn't be a determining factor for thermal expansion protection unless your refering to them installing a prv that closes the system is why they require it at that point. The thermal exansion tanks i install are 2.5 gal. I believe and weigh 2 pounds empty and approx. 22 pounds fully water logged. I've never had one break but you make a good point for larger tanks. 
thermal expansion tanks do extend the life of a water heater and can extend the life of the piping also.
There are ways to protect the home from a flooding expansion tank if you want to go through the trouble. I had a big problem with this very issue and the expansion tank causing a flood and never got a real answer other than the one i just gave you and to use another method of thermal expansion control than a tank where the structure could be damaged by failure.


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## service guy

TXTs are a Code requirement here on any water heater tank connected to a city water meter. Period.


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## TheMaster

service guy said:


> True TM, good point. Someone could close a valve to the tank while its heating. But 99% of the time, if a valve is closed for any length of time, the heater will be shut off anyway.


 I had a customer who worked out of town alot. He had a open system with no check valves or prv's anywhere. Every time he left town he would stop at the meter out by the street and turn his water off. This closed his system for 3 or 4 days at a time. He did not do anything else...just leaves town...water heater and everything else still energized. His reason was when he gets back home he has hot water to shower with but doesn't want to come home to another flooded house like he has done before. It cost me 2 trips to the house to figure all this out..he kept having PVC mip adapters fail at the copper/pvc connection at the house before it went into the slab. pvc MIP and fip adapters have 1/2 the pressure rating as the pipe and its a weak spot. I started asking questions and thats what he told me he was doing. I installed him an upsized expansion tank and the problem was solved. This was before tankless water heaters were as common and he said he wanted hot water when he got home so thats the only way i could come up with to do it.


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## Protech

I'm a big fan of thermal expansion valves. Unlike tanks, they fail in a way that lets the owner know there is a problem. They fail "safe" where a tank fails unsafe.

If an expansion tank fails, the pressure will climb and a hose or supply line may burst.

If an expansion valve fails on the other hand, it just starts dripping constantly and the HO has it replaced.


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## Phat Cat

Sometimes an expansion valve is the only option. 

Local condos have water heaters stuffed in closets under the A/C units. With new heaters having more insulation and being larger in diameter, oftentimes we need to remove the door and sometimes trim to replace the water heater. Absolutely no room for an expansion tank. :no:


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## Optimus Primer

PlumbCrazy said:


> Sometimes an expansion valve is the only option.
> 
> Local condos have water heaters stuffed in closets under the A/C units. With new heaters having more insulation and being larger in diameter, oftentimes we need to remove the door and sometimes trim to replace the water heater. Absolutely no room for an expansion tank. :no:


It should be illegal to put a heater under the a/c. Man that sucks changing those out. Or even worse are the ones in the kitchen cabinet and they cut the bottom of the cabinet out so it can fit. You know they plumbed it before the counter top went in.


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## TheMaster

PlumbCrazy said:


> Sometimes an expansion valve is the only option.
> 
> Local condos have water heaters stuffed in closets under the A/C units. With new heaters having more insulation and being larger in diameter, oftentimes we need to remove the door and sometimes trim to replace the water heater. Absolutely no room for an expansion tank. :no:


 I have extend a pipe to a location that would not be damaged if it flooded or for space requirements. Come off the W,H feed after the stop valve with a tee and run a pipe to your safe or roomy tank location. Some people dont like the other methods for expansion control other than a tank. I could careles either way aslong as the jobs done.:thumbsup: I have also developed a way to protect a home from flooding due to a bursted expansion tank that costs about 5.00......thats if the water heater has a drain pan or a remote tank located were an drain can go outside to to a suitable drain,


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## Phat Cat

house plumber said:


> It should be illegal to put a heater under the a/c. Man that sucks changing those out. Or even worse are the ones in the kitchen cabinet and they cut the bottom of the cabinet out so it can fit. You know they plumbed it before the counter top went in.


:laughing: We've been in most buildings, so we know where they 'hide' the heaters. Always fun to send the new guy to a condo and have him call the office to report he cannot find the water heater. It's behind the panel in the bar area, under the kitchen counter. :yes:

These are old buildings, so that's just the way it is. Hate to get the call of possible busted water heater only to find A/C leaking. :furious:


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## Master Mark

*good idea,,,,*



Protech said:


> I'm a big fan of thermal expansion valves. Unlike tanks, they fail in a way that lets the owner know there is a problem. They fail "safe" where a tank fails unsafe.
> 
> If an expansion tank fails, the pressure will climb and a hose or supply line may burst.
> 
> If an expansion valve fails on the other hand, it just starts dripping constantly and the HO has it replaced.


 
the thermal expansin valves I have never considered
installing, usually you need a drain somewhere near by to pipe a clear hose to....


but I think that they are a better idea than the tank
and could be a good sales item....especially if you got to change out the stop anyway....

if they need a stop anyway, you kill two birds with one stone...

what do they cost?? probably about 30 bucks would be my guess,,,

 I guess you could pipe it to a near by drain or a condensatin pump or to the laundry stand pipe

so what ahappens if you dont have a place to pipe the drain to, do you guys just leave the thinG pissing in the wind like the t+p valve does on many installs???

I am going to have to look into those , I never considered them but I agree with you that they are a better alternative to the thermal tanks...

thank you


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## Phat Cat

Expansion valve costs a little more than a sm. exp. tank.


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## Protech

I get my valves for less than $8. Am I missing somthing?


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## Master Mark

*8 bucks for expansion valves?????*



Protech said:


> I get my valves for less than $8. Am I missing somthing?


 
If you can get a ball valve (any brand)
with the little expansion thingey 
built on it for 8 bucks each, send me 100 of them...

do you take master card???:thumbup:....


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## Protech

I meant just the expansion valve.


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## Master Mark

*then what*



Protech said:


> I meant just the expansion valve.


 
so what are you doing then,,,,

are you just installing the little expansion valve in line with some sort of 
a reducer and tee near the heater????

for 8 bucks, 
it seems like a good idea if that is the plan....


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## uaplumber

I will only install an expansion tank if close to a pump with a check (grunfos EQ etc). Otherwise, our water is supplied at ~ 60 psi. Our code asks for a shut off on the cold only (99.9%) of installs.

It is not needed on most installs here and is not installed.
Piping the T&P to within 12" of the floor is a must, Cutting the blow down to 45 degrees to prevent theading or hose install is just a good idea.
95% are in concrete basements next to a floor drain so pans are not necessary.


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## Ron

I can tell you, and I have been to alot of homes, I don't see expansion tanks here. I don't install them, never called by any inspector here.


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## Christina

pauliplumber said:


> How important do you think it is for a expansion tank to be installed on a water heater?


Since 500 is the new business lounge requirement... I gotta get busier! 

I attended a CEU course in OKC with several plumbing inspectors and contractors across the state. Some municipalities did require them in their regions and others did not. The town that I am in does not. I do not have my code book with me but it is in IPC when there is a backflow prevention device in the system. And unless you did not design the system, install the system, replumb the system, test the system... you have now idea. Which is why some cities did and some didn't and still don't require.

Edmond, OK (I believe) was the town that they spoke of with a new water meter replacement program. They were changing out all water meters in the city one section at a time. The problem was that the water heaters did not have expansion tanks and the new meters had built in backflow prevention in them. They handed us all fliers (unsure if it was BW or Amtrol) but they showed pictures of water heaters that the tops had caved in, some they had blown out. Here is a flier, but not the one I saw.

http://www.amtrol.com/pdf/MC4090 06_07 TXT Brochure.pdf

The City of Edmond/ maybe it was Norman, but they had to replace the water heaters that had malfunctioned due to this issue. I will see if I can find a link to the issue and copy it to this thread.

Anyways, a few months later, I was called to a water heater that kept going out. As previously posted:








*My first experience with expansion tanks...* 
The bad part about living in rural America. We run about 10 years behind on EVERYTHING!! So, I had went to my plumbing inspector's furthering education classes, went to all my journeyman required continuing education courses and no matter where I looked, it was code, when there is a back-flow prevention device, a check valve, hmmm... a dang water softner??

Anyways, my father never did new construction while employed for himself. He did for the union but just doesn't care for it. So, a lot of times we go in after the 'new' guy. So, after I came to work for my dad in April 07 I was given a call. My mom screamed that Shawn had been out there and Mark and Kevin and... you get the point. So, I go out there, indeed the water heater is leaking from the bottom AGAIN :furious:!! 
WOW! Imagine that!! Now please note- that we live in rural America where check valves may not be at the meter... so they start us out small with back-flow on the outside hydrant. Please... don't laugh! :laughing:

Anyways, when they built this house, 3 years prior.... BRAND NEW!! Guess what? New Meter!! And what does this mean class?? Ohhhhh, and what is that? Not six foot away in the same closet... It has a lid type thingy on it, the lines on the top of the thing says in> and >out... Oh, wait there is some size 14 font... WATER SOFTNER!! Strike two! Holy cow! I put in their fourth water heater (OK, so there was a short in the jacket of the 4th so all technicalities it was their 5th) but anyways... 
ONE NEW WATER HEATER, ONE EXPANSION TANK, NO CALL BACKS!! :thumbup:

So, there is my story... on expansion tanks!!


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## Pipedoc

Christina said:


> .................Anyways, when they built this house, 3 years prior.... BRAND NEW!! Guess what? New Meter!! And what does this mean class?? Ohhhhh, and what is that? Not six foot away in the same closet... It has a lid type thingy on it, the lines on the top of the thing says in> and >out... Oh, wait there is some size 14 font... WATER SOFTNER!! Strike two! Holy cow! I put in their fourth water heater (OK, so there was a short in the jacket of the 4th so all technicalities it was their 5th) but anyways...
> ONE NEW WATER HEATER, ONE EXPANSION TANK, NO CALL BACKS!! :thumbup:
> 
> So, there is my story... on expansion tanks!!


Do softeners have check valves? Or is there another reason that requires the expansion tank when one is installed?

Okay, I know I'm gonna get picked on for this one but I don't have much experiance with working on softeners. It is an area I am definately going to explore more though.


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## Protech

yep. 3/4x1/2x3/4 tee with the valve on the 1/2" leg



Master Mark said:


> so what are you doing then,,,,
> 
> are you just installing the little expansion valve in line with some sort of
> a reducer and tee near the heater????
> 
> for 8 bucks,
> it seems like a good idea if that is the plan....


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## TheMaster

What brand and model do you use of valve?


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## Protech

I don't know. The brand the supply house guy hands me.


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## Master Mark

*good idea*

basiclly you are just installing the little part that
you see jutting out the side of a 60 dollar watts ball valve...

I would guess it looks a little wimpy compaired to putting the whole 60 dollar watts valve in but it has to do the exact same job....
it is the same valve..... and it is probably easy to fix

for that price, I could tie an extra valve to the line in case the one
were ever to fail, and the customer could change it out themselves 



you are not having any troubles with this at all ..correct?/


going to have to ask my supplier if they sell it that way


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## Leakinator

On every water heater I install an expansion tank and I also replace a lot because they are not pressurized to the house pressure. Can you guess why they come preset at 35psi?


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## Master Mark

*preset at 35*



Leakinator said:


> On every water heater I install an expansion tank and I also replace a lot because they are not pressurized to the house pressure. Can you guess why they come preset at 35psi?


 
they probably come preset at 35 becasue that is probably the suggested operateing pressure for them

if you pump them up to 75 or more it probably stresses them out very quickly...

they are not worth a damn, 

I am seriousely going to look into those little valves...

you cant beat the price and as long as their is a
drain near by , you cant lose.....


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## TheMaster

Make sure the valve is ASME certified if its required by your code.


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## Master Mark

*thank you*



TheMaster said:


> Make sure the valve is ASME certified if its required by your code.


I am going to ask protech more about what kindo f valve he is useing ......or get hold of his supply house
myself if he has the number ....

I am sure he can plug me into it....

I would guess that just to sell them to plumbers
they preobably already are certified..

unless they come from our 
"chinese global tradeing brothers" .
who knows , they might be made of 70% Zinc 
instead of brass , just like the Zurn pex fiasco......


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## RossThePlumber

*Thermal Expansion valves on Water heaters instead of Expansion Tanks*

Has anyone ever used these valves in place of the bulky expansion tanks on Water Heaters. I have an open sight drain below to tie this into.. I just hate the look of these stupid expansion tanks in a little mop closet and these seem perfect...ANY INPUT would be appreciated..i've never seen them before today. Click on the link below to see the valve I'm talking about... Scroll down to the bottom of the page for a pic of it's application.. 
Hope everyone is having a great week...
Godspeed
Ross


http://www.zurn.com/operations/wilkins/pdfs/specsheets/BV-BVEC.pdf


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## RossThePlumber

Oh Yeah.. It says the valve retails for about $40 in my book. That's list price..


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## Master Mark

*nice pic*

if you are talking about the whole Watts ball valve assembly that runs about 60 bucks....

All protech is talking about is just the little valve that is
screwed into the side of that watts ball valve....

he claims they are about 8 bucks each plus the fittings to adapt it to the copper pipe and the hose to the drain.. $12.00 that is dirt cheap if it is fo rreal

I am calling my salesman now....


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## Phat Cat

Ours cost $33.34.


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## Master Mark

*for the whole valve???*



PlumbCrazy said:


> Ours cost $33.34.


you are talking abou the whole expansion ball valve, correct???

that is not too bad either.. what brand???


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## ASUPERTECH

PlumbCrazy said:


> Sometimes an expansion valve is the only option.
> 
> Local condos have water heaters stuffed in closets under the A/C units. With new heaters having more insulation and being larger in diameter, oftentimes we need to remove the door and sometimes trim to replace the water heater. Absolutely no room for an expansion tank. :no:


 
I've put exp tanks, under sinks, in vanities, etc. There has to be some sort of thermal expansion device on the system can be any where or of many different options for this cause. "T" in under K.S. and connect Exp. tank HO may not like giving up the space, but when the inspector comes and sais your plumber is genius, it all works out.


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## Phat Cat

I don't know, the one the supply house gives us. :laughing:

I'm not going into the shop today. Tomorrow I will post the picture of it and the brand.


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## ASUPERTECH

PlumbCrazy said:


> I don't know, the one the supply house gives us. :laughing:
> 
> I'm not going into the shop today. Tomorrow I will post the picture of it and the brand.


Not going in??? Sick or VAC.?


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## Phat Cat

ASUPERTECH said:


> Not going in??? Sick or VAC.?


Neither - need some 'me' time.


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## Protech

they make that valve with pex barbs. sweetness:thumbup:



RossThePlumber said:


> Has anyone ever used these valves in place of the bulky expansion tanks on Water Heaters. I have an open sight drain below to tie this into.. I just hate the look of these stupid expansion tanks in a little mop closet and these seem perfect...ANY INPUT would be appreciated..i've never seen them before today. Click on the link below to see the valve I'm talking about... Scroll down to the bottom of the page for a pic of it's application..
> Hope everyone is having a great week...
> Godspeed
> Ross
> 
> 
> http://www.zurn.com/operations/wilkins/pdfs/specsheets/BV-BVEC.pdf


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## ASUPERTECH

PlumbCrazy said:


> Neither - need some 'me' time.


GOOD FOR U
:thumbsup:


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## Phat Cat

ASUPERTECH said:


> I've put exp tanks, under sinks, in vanities, etc. There has to be some sort of thermal expansion device on the system can be any where or of many different options for this cause. "T" in under K.S. and connect Exp. tank HO may not like giving up the space, but when the inspector comes and sais your plumber is genius, it all works out.


1. Well, the device of choice is the thermal expansion valve. 
2. Condo owners definitely don't want to give up the space.
3. Inspector :laughing::laughing::laughing:. They don't inspect water heater installations in this jurisdiction. The town is a resort area and the town's revenue is generated through tourism. Some condo buildings - relief valves/drain pans not piped to outside of building or even a drain for that matter. These buildings are grandfathered in.

I have a question, so if it sounds ignorant - please be kind.

Assuming there is a backflow at the meter (I'm not 100% certain), in a condo building that has all electric water heaters, wouldn't thermal expansion be rare? In other words, whenever anyone uses any water isn't the expansion relieved on the system. What are the odds the entire system is completely closed for any length of time? For argument's sake though, even if all was closed up - wouldn't the T&P valves relieve expansion and excess pressure? 

We have not run into any water heaters that have shown evidence of thermal expansion.


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## Phat Cat

Master Mark said:


> you are talking abou the whole expansion ball valve, correct???
> 
> that is not too bad either.. what brand???


Yes, the whole expansion ball valve.


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## Cal

Can't get a price tonight ,

http://www.watts.com/pro/_productsFull.asp?catId=64&parCat=292&pid=564&ref=2


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## Christina

Christina said:


> Edmond, OK (I believe) was the town that they spoke of with a new water meter replacement program. They were changing out all water meters in the city one section at a time. The problem was that the water heaters did not have expansion tanks and the new meters had built in backflow prevention in them.... ...The City of Edmond/ maybe it was Norman, but they had to replace the water heaters that had malfunctioned due to this issue. I will see if I can find a link to the issue and copy it to this thread.


This is not the City of Edmond's post but info I found from a plumber there on his page (http://www.logansplumbing.com/tips_hints.php)

*
Thermal Expansion Tank. Upon replacement of a water heater in the city of Edmond, a thermal expansion tank must be installed to prevent excessive pressure from building inside your water lines. 
Thermal expansion or the expansion of liquid when heated, can cause serious problems for a water heater. If this pressure is not relieved, it could result in the bulging or rupturing of the water heating tank. Water is a non-compressible fluid and expands when heated. As a water heater begins to heat and the temperature rises, it builds pressure. In the past, this pressure has been absorbed back into the city water lines. The city of Edmond has begun to change water meters to new ones that will no longer allow this pressure to absorb back into the city water supply.
*


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## Cal

We have had A LOT of meter w/ checks in them installed over the last few years . Not a lot of thermal expansion problems . However ,, I did price the thermal exp Apollo ball valve at my supplier $40 . Has a 3/8" copper compression fitting that needs some tubing piped to the floor , pan or drain . After seeing several exp tanks rupture ( bladder ) I'm thinking this is the new way to go !!

.02


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## Master Mark

*Protech...Who is they???*



Protech said:


> they make that valve with pex barbs. sweetness:thumbup:


 
My plumbing supplier is stumped.....
Could you put your plumbing salesmans guys number you buy these from down here or PM me with it so I can get the parts number from them>>>

if they are 8 bucks, I got to try them...

thank you


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## Protech

PM sent


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## Christina

Reading through the proposed code changes to be reviewed in Baltimore next month for 2009-2010. Thought you guys may want to read it... 

*P9–09/10*​*305.3.1 (New)*​*Proponent: *​​​​Ronald L, George, CIPE, CPD, President of Ron George Design & Consulting Services representing
himself​
*Add new text as follows:
305.3.1 Thermal expansion calculations​*​​​​. Where a piping system design has straight runs of piping exceeding 100
feet in length, the designer shall submit calculations and design drawings to the code official indicating the changes in
pipe length due to the difference between installation temperatures and the anticipated hot and cold service
temperature extremes. The drawings shall indicate how the changes in pipe length will be accommodated.​
*Reason:​*​​​​Thermal expansion occurred in a high rise building where the contractor made a material substitution the riser grew significantly and ripped
apart several joints when the system was brought up to temperature. This code change is intended to assure that thermal expansion issues have
been properly addressed by the designer and system installer.​
*Cost Impact:​*​​​​Minimal.​
Public Hearing: Committee: AS AM D
Assembly: ASF AMF DF​ICCFILENAME: GEORGE-P2-305.3.1 NEW


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## Protech

They are referring to thermal expansion of the pipes in that citation, not hydraulic thermal expansion.


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## gusty60

Protech said:


> They are referring to thermal expansion of the pipes in that citation, not hydraulic thermal expansion.


 Thank you


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## bchplumbing

Hmmm. My father in law has hot water heat (Radiator bases boards in his home. The installer installed an expansion tank two feet from the floor tank side down. the expansion tank is water logged and the TP valve drips constantly when in use. The water pressure has risen over 200psi. I shut the system down and... 

He also has gas heat as well, so I switch him to gas while I am investigating this issue. i think the tank is upside down and to low. I 'll get a pic and show you all soon.


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## futz

bchplumbing said:


> Hmmm. My father in law has hot water heat (Radiator bases boards in his home. The installer installed an expansion tank two feet from the floor tank side down. the expansion tank is water logged and the TP valve drips constantly when in use. The water pressure has risen over 200psi. I shut the system down and...


If it's a regular diaphragm expansion tank then tank down is the proper way to install it. Years ago we used to install them upside down (tank up) and high above the boiler (to get them out of the way) and they would fail prematurely. High and tank up is the old fashioned way for an old-style non-diaphragm expansion tank. Here's a couple pics (new boiler - partially prefabbed) of how I do it now:















I hang it from an air scoop with an auto air vent on top. I plumb the boiler water feed into the tee just above the expansion tank .

Expansion tanks don't last forever. If it's waterlogged, the diaphragm has probably failed. Replace the tank, and replace that pressure relief while you're at it. It will probably never again seal properly now that it's been dribbling for a while. Chances are the fill valve and backflow preventer are ruined too - depends on how long that exp tank was waterlogged before someone noticed the pressure relief dribbling.

Here's a pic of an install from a couple years ago:










> He also has gas heat as well, so I switch him to gas while I am investigating this issue. i think the tank is upside down and to low. I 'll get a pic and show you all soon.


He has a boiler AND a furnace? Isn't the boiler considered to be "gas heat"? I'm confused.


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