Location of expansion tank?

[itsr-ent]

I would like to locate my expansion tank near my water meter instead of near the water heater. I've read it's OK to have it anywhere in the system, but if installing it off the water heater's cold line make sure it's between the shut off valve and water heater so the valve can't isolate it from the water heater.

Not being able to isolate the expansion tank from the water heater makes perfect sense.

However, if you put the tank somewhere else (such as near the water meter after the PRV like I want to do), aren't you now able to isolate it? If you turn off the cold water shut off near the water heater, the extra pressure created when the water is heated can't get back to the expansion tank. It would expand into the hot water pipes where there's no expansion tank.

 

[Reach4]

Read the documents for your expansion tank. I maintain that if it were important that the expansion tank not have the water heater water shut off valve between the tank, the instructions would say so.

However, if you and Jim want to allow for shutting off that valve without also shutting off the water heater, then go ahead and worry about it. With your logic, people with a well and a 44 gallon pressure tank would also need a thermal expansion tank.

 

[Sponsor]

 

[itsr-ent]

Read the documents for your expansion tank. I maintain that if it were important that the expansion tank not have the water heater water shut off valve between the tank, the instructions would say so.

However, if you and Jim want to allow for shutting off that valve without also shutting off the water heater, then go ahead and worry about it. With your logic, people with a well and a 44 gallon pressure tank would also need a thermal expansion tank.

Who is Jim?

I get what you're saying -- if the supply to the water heater it shut off for an extended period of time, the water heater itself would usually be off for maintenance, etc. and it wouldn't be an issue.

The Amtrol documentation says to install it between the water heater and the PRV (or backflow device), but does not mention specifically installing it between the water heater cold supply valve and water heater.

 

[Jadnashua]

We have this 'discussion' each time it comes up...to function, there cannot be a valve between the WH and the ET. Not all 'users' understand what they are or how they work, and could easily decide to turn a valve off, then wonder why things are now leaking out of the T&P valve, or a hose bursts. Or, they know, but forget, or, they sell the house and someone that doesn't have a clue just fumbles into the situation where it is isolated. If installed 'properly', it won't matter, since it can always work. All of the installation diagrams show it installed this way. One way to think about a check valve is that it is a one-way valve. They do not allow a check valve between the WH and the ET. A shutoff is an expansion of a check valve, and functionally, works in the same manner, at least in one direction. Install it wherever you want, but if you want it to always be able to work, do not put a valve between it and the WH inlet. FWIW, most are not designed to work on the hot water side, but there are exceptions, but if you do place it there, don't expect it to last as long as if it is on the cold side. ANd, if located there, after awhile, any water stored in it will cool off, and just add to the cold water that has to be purged from the line before hot arrives at its destination.

 

[itsr-ent]

We have this 'discussion' each time it comes up...to function, there cannot be a valve between the WH and the ET. Not all 'users' understand what they are or how they work, and could easily decide to turn a valve off, then wonder why things are now leaking out of the T&P valve, or a hose bursts. Or, they know, but forget, or, they sell the house and someone that doesn't have a clue just fumbles into the situation where it is isolated. If installed 'properly', it won't matter, since it can always work. All of the installation diagrams show it installed this way. One way to think about a check valve is that it is a one-way valve. They do not allow a check valve between the WH and the ET. A shutoff is an expansion of a check valve, and functionally, works in the same manner, at least in one direction. Install it wherever you want, but if you want it to always be able to work, do not put a valve between it and the WH inlet. FWIW, most are not designed to work on the hot water side, but there are exceptions, but if you do place it there, don't expect it to last as long as if it is on the cold side. ANd, if located there, after awhile, any water stored in it will cool off, and just add to the cold water that has to be purged from the line before hot arrives at its destination.

Ah, OK. Sorry -- I did search and found multiple posts about it being OK to put anywhere, but no one seemed to mention that doing so puts a valve between the water heater and expansion tank. I just wanted to make sure I wasn't missing anything and that I understood it properly.