Expansion tank and PEX pipes

[skitchin]

Will this work or do I need to have a stainless strap around the tank with wire hanging it to roof truss? I know PEX is pretty strong but I'm not sure if it can actually hold the expansion tank. Your thoughts?

 

[Jeff Handy]

Needs support.

Maybe a wire on each side of the tank, for even support.

One wire hanging from each side of the rafter.

 

[Jeff Handy]

Is there a catch pan with a plumbed drain, under that heater?

And is the relief valve plumbed to a drain?

 

[skitchin]

Needs support.

Maybe a wire on each side of the tank, for even support.

One wire hanging from each side of the rafter.

That is what I was thinking.

 

[skitchin]

Is there a catch pan with a plumbed drain, under that heater?

And is the relief valve plumbed to a drain?

There is catch pan with drain pipe under the water heater but expansion tank isn't.

 

[Jeff Handy]

Very good.

Will the relief valve discharge into the pan if it leaks or blows?

 

[skitchin]

Very good.

Will the relief valve discharge into the pan if it leaks or blows?

No. The expansion tank and water heater are both new. I had it replaced last year and I did the PEX piping myself.

 

[Jeff Handy]

Your answer makes no sense.

I am asking if the discharge from the temperature and pressure relief valve drain pipe will be caught by the drain pan.

I am asking nothing about the expansion tank or the water heater itself.

 

[skitchin]

Your answer makes no sense.

I am asking if the discharge from the temperature and pressure relief valve drain pipe will be caught by the drain pan.

I am asking nothing about the expansion tank or the water heater itself.

My mistake. Yes the pressure relief valve and valve drain pipe goes to the drain pan.

 

[Jeff Handy]

Then that water will come through your ceiling.
That is my point.

 

[HWSleuth]

Will this work or do I need to have a stainless strap around the tank with wire hanging it to roof truss? I know PEX is pretty strong but I'm not sure if it can actually hold the expansion tank. Your thoughts?

Jeff is right on with supporting the tank. Yes, PEX will support the tank when it’s new and operable. However, when the tank’s diagram fails and the tank fills with water, it’s total weight will become something the PEX pipe and fittings may not support.

 

[skitchin]

Is this better?

 

[Jeff Handy]

I think that looks pretty good.

 

[sarg]

I have to ask ...... why do folks install these expansion tanks hanging down where if they fail & fill with water the weight at 8 pounds+ per gallon tears the pipes down ?
If these tanks were installed "on top" with the threads on the bottom they would not fill up even if the internal bladder failed and would never jeopardize the piping.

 

[Jeff Handy]

I think if the bladder fails, even a tank going upward will eventually fill with water, as the leaking air is absorbed.

 

[sarg]

Gonna have to think that over awhile to get it.

 

[Jeff Handy]

The fact that water gradually absorbs trapped air is the reason there needs to be a bladder in an expansion tank, or a pressure tank for a well.
To separate the air, so it can do its job without being carried away with the water that flows through it.

I had a big old galvanized well tank with no bladder.
It worked fine, because it held a big volume of trapped air on top, that acted like a spring, to lengthen the on/off cycles of the pump.
But I had to occasionally put a tire pump onto the air valve and add more air, when I heard the cycles getting too short.
The trapped air was being drawn down gradually, by absorption, and released from my faucets.

A ruptured bladder on an expansion tank will gradually compress and shrink, and let more water gradually fill the tank.
Water pressure will collapse the bladder.
Water can easily go uphill in the tank.

If any of this is wrong, pros please feel free to correct me or improve on my convoluted story.

 

[skitchin]

I have to ask ...... why do folks install these expansion tanks hanging down where if they fail & fill with water the weight at 8 pounds+ per gallon tears the pipes down ?
If these tanks were installed "on top" with the threads on the bottom they would not fill up even if the internal bladder failed and would never jeopardize the piping.

Most manufacturers recommend it in hanging position with support. Mounting it to the pipe sideway or inverted position without support will trap air and it may break off when the tank fails.

 

[arctic bill]

just so that you know, in the plumbing code thing like the expansion tank should be supported independently of the piping.

 

[Twowaxhack]

I have to ask ...... why do folks install these expansion tanks hanging down where if they fail & fill with water the weight at 8 pounds+ per gallon tears the pipes down ?
If these tanks were installed "on top" with the threads on the bottom they would not fill up even if the internal bladder failed and would never jeopardize the piping.

I have a better question.
Why do codes allow an expansion tank to be installed on top of a water heater......

But requires a water heater to be in a pan.....

Have you ever read the instructions that come with an expansion tank ?

It clearly states do not install where water damaged will occur if it leaks.

Also a relief line IMO be piped to outside or to a suitable drain.
There’s no way a water heater pan drain can take the full discharge of an over heated water heaters relief valve discharge before it overflows.


My point is that just because it meets code doesn’t make it good plumbing.

Code is minimum standards.....

Fact is that some inspectors snd code writers are FAILED plumbers and contractors.......

I’m a 3rd generation master plumber and these are my experiences.....and my fathers and my grandfathers and about 7or 8 uncles and cousins that are all licensed plumbers. Just to give you a reference from where I’m getting my info. It’s not online or in a book.