elevated exchangers in a 806 gal tall storage tank

[sweetheat]

anyone with knowledge of proper exchanger installation in the STSS 806 gallon tall tank please respond to this post. We are trying to determine the best way to elevate the 3 heat exchangers off the bottom of the EPDM liner. Tarm suggests cement blocks wrapped in 6 mil poly. Will a schedule 40 PVC cradle support it better? Wood has been discussed but will affect the PH of the water. Will schedule 40 PVC work with 180 degree water over a 20 year span? What about plastic milk crates? Will 180 degree water affect it over time? many thanks for your response from sweetheat

 

[Nofossil]

For mine, I used vertical 1/2" hard copper pipes tied and soldered to the exchangers with 10ga copper wire. The bottom of each 1/2" copper pipe sits in a 3/4" CPVC (high temperature PVC) end cap.

I was just trying to avoid having the copper touch the stainless, but it seems like it would work for your situation as well.

 

[free75degrees]

I was just planning on leaving the copper tube sitting on the epdm in my homemade tank. Do you think this will be a problem? Why are you planning to elevate it?

 

[Dave T]

It takes very little loose movement back and forth on .045 mill EPDM to (saw a hole) and work through small layers at a time causing weak spots in the roof or in this case the liner..The idea of using plastic coasters like Hi temp PVC caps is a cheap investment and good insurance plan..There may be better reasons for elevating the coils but from a roofers aspect 180 degree hot copper laying in direct contact with EPDM is not the best choice for system longevity..Entering or exiting the tank the EPDM will flex with the copper because it is tight and usually clamped no sawing movement
DAVE

 

[free75degrees]

Thanks dave. So maybe the cement block idea is a good one with epdm because heavy blocks would help ensure that any movement is between the block and the copper. Feet attached to the bottom of the coppper coils may just translate any movement to the feet and we'd still have friction between the feet and the epdm.

Marc

 

[sweetheat]

the STSS 806 tank is 72 inches high and 64 inches in diameter. the tank is designed to fit under my stairs to the 2nd floor. the heat exchanger coils need to be located in line with the holes in the tank up in the hottest water. the coils are only approx 48 inches high. sweetheat