Installing Expansion tank, on top or bottom?

Old 10-11-06, 02:40 PM
pamspam's Avatar
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Join Date: Aug 2006
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Question Installing Expansion tank, on top or bottom?

Hi after reading all the posts in this forum on our problematic TPV leak we concluded we need an expansion tank.
We have a GE Smartwater 50 gal. tank (installed by previous owner Sept. '05).
My husband bought a little Watts DET-5 Expansion Tank at Home Depot tonight hoping to install this on Saturday.

Question: we read from "ask the Builder" website he mention to install expansion tanks on TOP never on bottom, but most diagrams online all show tanks installed under tha main pipe. The Watts diagram shows on top is an optional way for installing it.

Why would Ask the Builder say to install it on top?
Since our TPV valve has probably been leaking since the previous owner installed it (a yr ago) would you advise replacing the TPV valve for safety reasons and get a new one?
It leaks approx. 4 time per month about 1/2 - 1 c. of water.

Thank you for all replies!
Old 10-12-06, 05:52 PM
Join Date: Mar 2006
Location: Wet side of Washington state.
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Yes, you should replace the T&P valve, cheap insurance.

As for the expansion preference is to install them with the tank above the point of connection as it will reduce or eliminate the possibility of "stale" water collecting in the tank. You may need to fabricate some sort of supporting means for the tank.

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