dead end & DHW expansion tank

Boon

Just read another thread that mentioned dead ends & Legionella. Now I'm freaking out about the 9" of pipe to my DHW expansion tank being a dead end. Is 9" to an DHW expansion tank too far? The inspector noted the tank during the rough-in inspection but didn't say anything else about it.

EBEBRATT-Ed

Is the expansion tank for your boiler that heats your home?? or is it an expansion tank on the hot water heater that heats domestic hot water for showers etc.??

If it is a boiler expansion tank than a dead end isn't a problem.

Leon82

Use two 90 and a tee to make a hairpin curve if you need the 9" for clearance.

Actually, 4 90s

Jamie Hall

9" isn't enough of a dead end situation to be a problem if it's on a well pump water line. Remember that about a third of that tank volume will move in and out with each cycle of the well pump.

You say that this is on your domestic hot water line, though, so I presume that this is not a pump control pressure tank, but on there because there is a pressure reducing valve or check valve between you and city water? Even so, it shouldn't be a problem. In comparison with the amount of hot water used the amount moving in and out of that pipe and tank is tiny.

EBEBRATT-Ed

Guess I'm going blind he did say it was a DHW expansion tank.

Boon

because there is a pressure reducing valve or check valve between you and city water?

Yes, I should've said that originally.
I'll stop worrying but now I see a different way to mount it so maybe I'll move it in the future. Thanks

hot_rod

Looks like products are being developed to address "dead-ending" of DHW expansion vessels.

EBEBRATT-Ed

Dam, why didn't I think of that. If I did I could retire!!!!!

Said that 1000times

Jamie Hall

Those should work very well. Jacuzzi made a variation on that, years ago. Haven't seen it lately.