1/2" MNPT Stainless Steel Tank (0.26 Gal)

This purchase was a warranty replacement. I got 4+, but not 5, yrs of multiple uses daily of the master bath's 7 gal water heater before the expansion tank failed. Per my calcs, the max expansion is about 0.11 gals so this 1/4 gal tank does the job. But if space permits the 1/2 gal version (ZS2) is not much bigger, close in price and probably what I should have purchased. The tank is stainless steel and one of the best made small expansion tanks that I can find.

We used this on a Bosch 7 gal water heater, installed inside a vanity to supply the master bathroom. Incoming hot water, from house tank, feeds the master bath water heater via a mixing valve which has a check valve. This expansion tank eliminated the T&P dripping due to the check valve. Perfect size, stainless steel and well made.

I used this tank for an odd install. In-vanity, 7 gal water heater's "cold" water feed is the house's main hot water tank. So we added a mixing valve to limit the incoming hot water to 115-120 degrees to avoid using more of the main hot water than the bare minimum. But the mixing valve had check valves, blocking the 7 gal tank's access to the main house's expansion tank. So I needed a small expansion tank to handle 115 to 140 "expansion" of the 7 gal tank. This ZS1 stainless tank is the perfect size, looks great, and has about a quart capacity. Stopped the 7 gal tank's T&P valve from releasing. I recommend Zilmet tanks as they are well-made.