Thermal expansion tank before WH @ copper flex

[vdotmatrix]

I installed a bypass on my water heater in 2004 with flex copper lines so i could do maintenance on the WH and not have to shut off water to the entire house.

The bypass makes this a non rigid system attached by the flex curley lines....really handy when i replaced the wh a month ago.

I just replaced the water heater and i sometimes find water in the bucket under the safety valve next to the water heater... i need to install a THERMAL EXPANSION TANK.

I bought one from Lowes (2gallon).

So no room anywhere for this thing and i thought if i could find a TEE to branch off the end of the cold water FLEX supply in the 3rd image, i could put the tank above the WH....the expansion tank would only be isolated whenever i would drain the WH twice a year .

The tee needs to be 3/4” female 3/4” male and the branch could be a 3/4” push fit...

Do they make such an animal..
Does this sound like a plan?
Thanks in advance.

 

[Themp]

You want the expansion tank to be accessible so that you can check the pressure at the Schrader valve. In the second picture, it looks like the cold water supply line is running along the ceiling away from the large air duct. Can you put a T on that line on the other side of the duct? Then hang the tank from the T, which puts the valve down for easy access.

 

[Sponsor]

 

[vdotmatrix]

Yes...but if you look closer, that duct is lined with asbestos and i just dont want to do anything to disturb that. The tank would live in the same spot in the ceiling no matter how i routed the cold water to it.....its just that at the point where the flex hose attaches to the rigid part of my system , i would only have to screw things together.....do they make a tee like that

You want the expansion tank to be accessible so that you can check the pressure at the Schrader valve. In the second picture, it looks like the cold water supply line is running along the ceiling away from the large air duct. Can you put a T on that line on the other side of the duct? Then hang the tank from the T, which puts the valve down for easy access.

 

[vdotmatrix]

The other thing i wanted to do was to isolate this tank in case something happens (leaks and so on) or i need to do thing to it....easy to bypass if on the WH loop. Thanks

 

[Reach4]

The other thing i wanted to do was to isolate this tank in case something happens (leaks and so on) or i need to do thing to it....easy to bypass if on the WH loop. Thanks

The tank is unlikely to leak. If it did, you would turn off the water, and replace it. The normal failure mode is that it stops accepting water because the diaphragm fails. In that case, you replace it. They are very common, and usually interchangeable.

 

[Themp]

If you have asbestos on the inside of the duct work, then I think that should be looked at. I see no asbestos on the outside of the duct work which was common in the 60's and earlier. Are you sure it is not some kind of fiberglass material? That duct work looks fairly new.

On the tank connection at the flex hose connection fitting you will probably want to use this:

https://www.pexuniverse.com/3-4-c-x-3-4-c-x-1-2-fpt-cast-brass-tee-lead-free-brass

This would let you screw in your tank. Now you have to modify the fitting that accepts the flex hose to insert the tee above. I would take off the flex connector fitting, make a 90 degree turn, add the above fitting with the screw connector down and then do another 90 down to the flex hose connection. The tank then hangs from the brass fitting. The support looks pretty solid on the pipes you added to isolate the WH, but check that out as the tank has some weight to it. Also, make sure the tank is not going to be heated by the WH flue. Heat on the expansion tank will mess with the diaphragm in the tank.

 

[vdotmatrix]

If you have asbestos on the inside of the duct work, then I think that should be looked at. I see no asbestos on the outside of the duct work which was common in the 60's and earlier. Are you sure it is not some kind of fiberglass material? That duct work looks fairly new.

On the tank connection at the flex hose connection fitting you will probably want to use this:

https://www.pexuniverse.com/3-4-c-x-3-4-c-x-1-2-fpt-cast-brass-tee-lead-free-brass

This would let you screw in your tank. Now you have to modify the fitting that accepts the flex hose to insert the tee above. I would take off the flex connector fitting, make a 90 degree turn, add the above fitting with the screw connector down and then do another 90 down to the flex hose connection. The tank then hangs from the brass fitting. The support looks pretty solid on the pipes you added to isolate the WH, but check that out as the tank has some weight to it. Also, make sure the tank is not going to be heated by the WH flue. Heat on the expansion tank will mess with the diaphragm in the tank.

It is premium hi-test asbestos @ 51%; I had it tested when I worked at a reference lab about 15 years ago...House built in 1956. Trust me it is there...

I have everything in the house isolated with ball valves and it would be nice to install a TEE before the WH bypass to keep WH and expansion tank isolated in case I need to do anything so I do not have to cut off water to the rest of the house for any reason; women live here.

No golf today, have to take care of this.

So I just saw your link, I have some of those but I just want to insert a TEE between the flex connection FIRSTLY, then I can branch it to the expansion tank by sweat, screw or push connection.....

I am searching for that kind of TEE.....I want everything flexible after the bypass-the whole point of this setup......IDEALLY i want to be able to connect a FLEX lines to the TEE ( in, out and to the branch for the tank). IS there such a fitting?

Thank you for helping!

 

[vdotmatrix]

I decided the easiest thing to do is to put a 3/4” sharkbite tee in the middle of the cold water supply in the 1st picture, branch off with a short section of 3/4” and a section of sharkbite hose to the expansion tank...should make for a very neat job. I will post pictures once i am fnished. Thanks again.

 

[vdotmatrix]

The thermal expansion tank comes with 25psi from the factory, Can I pump this up to around 60psi before I install it on the tee branch?

 

[Reach4]

The thermal expansion tank comes with 25psi from the factory, Can I pump this up to around 60psi before I install it on the tee branch?

Pump expansion tank precharge air to the water pressure or pound or 2 more.

What thermal expansion tank comes with only 25 PSI air from the factory?

 

[vdotmatrix]

All 3models i saw at Lowes come pre charged to 25psi. so it doesnt matter whether i charge it up to the pressure i want before hanging it? the instructions say to do it as a last step but that may be awkward once it is mounted in the ceiling.

 

[vdotmatrix]

Another question, 24” branch to the thermal expansion tank ok? Thanks in advance.

 

[Reach4]

Interesting. Therm-X-Trol factory pressure is 50 PSI. http://www.amtrol.com/media/documents/thermxtrol/MC8520_08_14_TXT_Sizing_Chart.pdf
I think I remember that some thermal expansion tanks specify that the max precharge is 60 PSI. You might check the specs on your unit.

Another question, 24” branch to the thermal expansion tank ok?

No problem.

 

[vdotmatrix]

DOES it matter when I pump it up?

 

[vdotmatrix]

Interesting. Therm-X-Trol factory pressure is 50 PSI. http://www.amtrol.com/media/documents/thermxtrol/MC8520_08_14_TXT_Sizing_Chart.pdf
I think I remember that some thermal expansion tanks specify that the max precharge is 60 PSI. You might check the specs on your unit.


No problem.

http://pdf.lowes.com/useandcareguides/091194008460_use.pdf

 

[Reach4]

DOES it matter when I pump it up?

It does not. You could take it to a gas station if you like.

 

[Jadnashua]

The ET must be precharged BEFORE you apply water pressure to it, otherwise, it will just read the system water pressure once you've turned the water back on. It may be that they don't put all that much pressure in them at the factory is so that the bladder isn't stretched for a long time while it sits on a shelf prior to installation. When the precharge is the same as the system pressure, the bladder sits at a neutral point, and can accept the maximum amount of water without damage.

Make sure that the ET is specified for POTABLE water...those designed for hydronic heating (or maybe suitable for both) tend to come with a lower precharge, as hydronic rarely needs more than 15psi or so.

 

[vdotmatrix]

View attachment 42426 Another question, 24” branch to the thermal expansion tank ok? Thanks in advance.

WELL, it just occurred to me that unless I prefill this hose with water, there will always be an air bubble between the cold water line and the tank...OR hold the tank below the tee and hope the water displaces the air and the water reaches the tank and then I can just reach up and place it where it in the plumbing strap......I wrapped the tank with teflon tape and it leaks so I had to take it off rewrap or mybe use pipe dope. Anymore I may just start hiring licensed plumbers who know what they are doing.

 

[Reach4]

WELL, it just occurred to me that unless I prefill this hose with water, there will always be an air bubble between the cold water line and the tank..

That bit of air will be inconsequential.

 

[Jadnashua]

Just like in an air column people try to use as a hammer arrestor, they fail because the air eventually gets absorbed by the water...as said, don't worry about it.