Eastman 2-Gallon Mini Thermal Expansion Tank, Stainless Steel Hammer Arrestor with 1/2 Inch Threaded Connection, 60008

Think of an expansion tank as a shock absorber for your plumbing system. Every time your washing machine cuts off the flow of hot water by slamming a valve shut...; this device cushions the blow to all the pipes.

works like a charm on new tankless hot water heater

This micro expansion chamber is marketed principally for thermal expansion protection of in-line tankless or on-demand water heater systems, which it should be great for. A secondary use is for water hammer reduction, which is what I purchased it for. Pros include the fact that it is made by Eastman, a reputable supplier of thermal expansion protection products. I have a full size unit to protect my tank-based water heater system and have been very pleased. This micro-expansion chamber exhibits the same quality. Pros: good manufacturer; straightforward installation requirements; stainless steel construction. Cons: no installation or service instructions; incorrectly listed in the product description as having 2 gallon capacity (this is incorrect - it is meant for 2 gallon capacity tankless water heater systems but the chamber itself is likely about a cup in volume). As mentioned by another viewer, setting the pressure is very difficult. There is so little volume in the air-portion of the unit that getting the right pressure and then keeping it from bleeding off when you remove the air chuck is a challenge. In summary this is a very good unit possibly worthy of a 5 star review were it not for the difficulty adjusting air pressure, the need for installation documentation, and a necessary correction to the sales listing. The unit reviewed was made in China.

Passed the inspection in my new house. Doesn’t take up any room! Can you find it in the photo?

Worked perfectly as a very small expansion tank for the tankless DHW coil in my small residential boiler.

Had to get some brass T’s but once configured for washing machine works great

Not a two gallon damper. Was not sufficient for my home, had to buy another, correct unit.

I just added this to my tankless water heater. The issue I am having is my water pressure is at 80lbs and adding 84lbs to this is difficult. Every time I check for the right pressure I lose the pressure I need. This expansion tank is small but difficult to make work.