New Expansion tank installation....necessary ?

[rcatty]

I have a well, and just installed 2 new hot water tanks (50 gallon each). The system, besides being on a well, has a hot water recirculating line, with a grundfos pump, and a checkvalve (on the recirc line only).

My cold water line, traced back to the well, has a main shut off valve, wiring for the well pump, and a "dial/degree" shut off valve where the water line enters the house. I see no checkvalves or other items in the line.

Do I need to install a thermal expansion tank ? If so, the manufacturer instructions all indicate that the tank should be placed between the tank shut off valve and the tank itself. However, my shut off valve is located only about 5-6 inches from the tank. That leaves me a narrow spot to install the tank. Indeed, that area of the cold water inlet line often gets warm from the heat of the tank. Is it safe to install the tank at that spot? I can cut into that 3/4 inch pipe, place a tee, and extend a pipe out, and put a 90 degree with a female end and strap to the ceiling.

Is it safe to install a thermal expansion that close to the top of the tank itself? Thank you

[SewerRatz]

It shouldn't hurt at all. Maybe post a pic of your set up.

[kingsotall]

Trying to see if they have the tanks piped in parallel or series, Ron¿ ;)

[SewerRatz]

Trying to see if they have the tanks piped in parallel or series, Ron¿ ;)

No matter really, each water heater needs an expansion tank. But it would be nice to see :D

[kingsotall]

This OP has some nice descriptions of their setup. It is obvious there is some thermal expansion by the cold inlet being warm but they should consult their county code. Ours requires expansion tanks even without PRV's or checks in place. :confused:

[SewerRatz]

This OP has some nice descriptions of their setup. It is obvious there is some thermal expansion by the cold inlet being warm but they should consult their county code. Ours requires expansion tanks even without PRV's or checks in place. :confused:

Ours is going to start to require it. It mainly due to many villages putting in new meter yokes with built in duel checks. So they want the water heaters to already have the proper protection.

[kingsotall]

Makes sense. The fellas I work with will still think it's malarkey.

[rcatty]

Each tank needs an expansion tank? They are in parallel. How close can they be placed to the tank? I only have about 5 inches between the shut off valves and each tank.

[SewerRatz]

Close is not a problem. Some people put the expansion tanks a tad to far from the water heaters.

[99k]

Each tank must have an expansion tank, if you ever close that ball before the tank (otherwise the water will either puke out of the TNP valve from thermal expansion or may damage the tank during cool down). As it is, if you never shut the valve off before this tank (unless to replace the hot water heater) you really don't need an expansion tank (unless your code insists upon it). The reason being that the large diaphram tank for the well is acting as an expansion tank for both water heaters and accommodates any thermal expansion and contraction from the hot water heaters.

[rcatty]

What is the function of that large tank for the well. Is well water stored there for later use? Would you still recommend an expansion tank? If so, is it ok to place it about 2-3 inches above the inlet valve from the hot water tank ? Thank you.

[99k]

The water tank is a resevoir that allows you to store pressurized water in your home and prevents short cycling of the well pump. There is no harm installing a small pressure tank. My experience in our area is that most homes on a well do not have the small expansion tank since the larger well tank is performing the same purpose.

[rcatty]

Thank you for your answer. Assuming I were to put a tank in, can it be as close as 2-3 inches from the cold water inlet valve? Thank you, again.

[99k]

That is Fine.

[rcatty]

Ok, thank you. Finally, do I need a pressure relief valve, and pressure gauge on the tank lines? Or can I use the pressure reading on the well pump apparatus? Thank you.

[rcatty]

The Illinois Code only requires an expansion tank on closed systems.

I don't see any check-valves on the line running back to the large tank. Is there anything I need to look for? Or, on well systems do they never put a check-valve before the large well tank?

Thank you

[jadnashua]

Many pumps have a check valve in them at the bottom of the well. It is not recommended to have more than one, but people sometimes do that if the one in the well fails and they don't want to pull the pump to fix it (that doesn't always work, either). If you install an expansion tank for the WH, it can go anywhere on the cold inlet line between the shutoff valve and the tank. You can run the outlet of the T a ways to make installation of the tank easier, but the T must be between the inlet and the valve.

[SewerRatz]

The Illinois Code only requires an expansion tank on closed systems.

I don't see any check-valves on the line running back to the large tank. Is there anything I need to look for? Or, on well systems do they never put a check-valve before the large well tank?

Thank you

Most well pumps will have a check valve at the pump. Illinois is going to start to require them no matter what. Yes at this point in time it is only required to be installed on a closed system.

[hj]

Your well's storage tank is a "large" expansion tank and will perform exactly the same function as an expansion tank at the heater, except when the water supply is off to the heater and the water is being heated, which is not a normal situation and will seldom happen anyway in the normal course fo events.

[master plumber mark]

Your well's storage tank is a "large" expansion tank and will perform exactly the same function as an expansion tank at the heater, except when the water supply is off to the heater and the water is being heated, which is not a normal situation and will seldom happen anyway in the normal course fo events.


You dont need an expansion tank on a well,
as HJ already stated it is not necessary because you already
have a huge well bladder that is doing the same exact job for you

considering that most wells are normally around 50-60 lbs,
the water pressure will never rise high enough on a well to ever
cause the pressure relief valves to ever pop off in the first place
It simply CANNOT pop off because you have the well tank as a huge back up...........


so just save your money ,
or better yet take the wife out to dinner with it.
(dont tell her why)..

[SewerRatz]

I do not agree that a well tank is a suitable expansion tank. Since it will not meet the letter of the code here in Illinois. Bold added by me. I do agree that the well expansion tank can handle the job, but we must follow the plumbing codes in our local areas.

A properly sized and approved expansion tank shall be located on the outlet side of the check valve in the water heater's cold water supply with no shut-off valve between the heater and expansion tank.

[rcatty]

My reading of the code indicates that an expansion tank is required on "closed" systems only. My understanding is that a closed system means one that has a meter, check-valve, or some other "back-flow prevent(er)" device, that would prevent water from backing up in the line.

Specifically, Ill Admin Code sec 890.1130 g. 7 reads, in part, : " Closed water systems shall have a properly sized thermal expansion tank ..........."

I see no other Code requirement for "open" systems, or water heater tanks in general.

[SewerRatz]

My reading of the code indicates that an expansion tank is required on "closed" systems only. My understanding is that a closed system means one that has a meter, check-valve, or some other "back-flow prevent(er)" device, that would prevent water from backing up in the line.

Specifically, Ill Admin Code sec 890.1130 g. 7 reads, in part, : " Closed water systems shall have a properly sized thermal expansion tank ..........."

I see no other Code requirement for "open" systems, or water heater tanks in general.

As I said in other posts there is no requirement "YET" for "open" sytsems. I do think you meantioned you have a well right? Most wells have a check vavle, which makes it a "closed" system.

[99k]

Most wells have a check vavle, which makes it a "closed" system.

The check valve is installed between the feed and the well tank (prior to the cross) and therefore the system is not closed

[SewerRatz]

The check valve is installed between the feed and the well tank (prior to the cross) and therefore the system is not closed

99k educate me here a bit. I will admit my well knowledge is nill. So there is a check valve between the feed from the pump and the well tank. Prior to the cross, meaning that you are saying the well tank would act as your expansion tank? From what I am getting if thermal expansion happens the check valve will prevent the water from pushing back into the well. To me that is a closed system. But maybe I am missing something.

Lets do say you are depending on the well tank to handle the thermal expansion. It would not meet the Illinois plumbing code then. The part it violates is the fact there is a shut off valve between the tank and the water heater. Also I am not sure on this one but the code does say "A properly sized and approved expansion tank" is the well tank approved for thermal expansion? But that does not matter since it does not meet the requirement for the location of the expansion tank. "shall be located on the outlet side of the check valve in the water heater's cold water supply with no shut-off valve between the heater and expansion tank. "

[rcatty]

Ron, but what you quote above , refers/applies to "closed " system. My understanding of the requirement for a tank, is an effort to avoid pressure build-up , where the cold water has no place to expand. Hence, the requirement for the tank between the shut-off valve and the tank. If one were to close the line by closing the shut-off valve, then you would have pressure build-up. A system would become closed at that point. However, the Illinois code is not mandating a tank for every system. Just permanetely closed systems.

[kingsotall]

The hot water would be the one doing the expanding. If there were a check on the cold side then in theory that cold line would then, yes, have no room to take any expansion from the hot side.