Regular Expansion Tank for Water Heater

[Size: 2.1 Gallon, Number of Items: 1]
We needed something compact for our water heater setup, and this 2.1-gallon tank fit into a tight space without any hassle. Installing it was super straightforward with the standard 3/4-inch MNPT connection, and we did not need any special tools or professional help to get it in place. It works great for absorbing thermal pressure and stopping annoying water hammer noise, which gives peace of mind for protecting the pipes, valves, and water heater from leaks and stress. For the price, it's a great value, and a no-brainer insurance policy for peace of mind.

[Size: 2.1 Gallon, Number of Items: 1, Size: 2.1 Gallon, Number of Items: 1]
Installed on existing cold water supply line before 1st of two water heaters in the Phoenix, AZ region. The house has a large tank hot water heater that supplies the major appliances and two bathrooms. A tankless heater feeds the hot water needs of another bath and a half. In Phoenix, thermal expansion occurs two ways. First, there is the standard heat from a tanked hot water system in a closed loop. However, during summers, the cold water supply lines that run along outside of the house walls are also subjected to a lot of thermal increase.Historically, when running the washing machine, knocks could be heard on the tankless side of the house. Installing anti-knock devices on the washing machine supply lines themselves only slightly reduced the problem. After installing the expansion tank, the issue appears to be alleviated. There is a slight noise that has not yet been pin-pointed as the washing machine goes through its cycles.After testing the house water pressure, the expansion tank valve pressure was increased to match. There was a lot of air leakage between the inflation device connector and the expansion tank's valve. The inflation device has been used regularly and does not typically have such an issue. Thus, I assume the valve is a bit on the narrow side. All that being said, while it took longer, the tank pressure was able to be inflated to 62 psi to match the internal water pressure.Install is rather simple once you get the parts to integrate into an existing system. For our needs, a brass tee was purchased with one end being 3/4" female NPT and the other two being 3/4" MNPT. The female end screwed onto the supply pipe to the tank. The original supply line coupling and the line to the expansion tank screwed onto the male ends. An additional 3/4 flexible line that screwed onto the tee and onto the expansion tank's threads was also required. See image. Please note the image was taken before the wall mounting bracket (also not supplied) was installed.From the research that I have done, the tank can be installed vertically with the air valve up or down. It can be installed horizontally but opinions lean toward decrease bladder life due to uneven wear.The total cost of a 2 gallon expansion tank, plus the additional items need for install, is under $100US. When compared to the cost of repair for a burst pipe, it certainly has a lot of value in homes where thermal expansion is an issue.

[Size: 2.1 Gallon, Number of Items: 1]
This water heater expansion tank is a well-built solution for helping protect plumbing systems from thermal expansion. The compact 2.1-gallon design fits easily into tight spaces, making it an excellent option where installation room is limited. The durable construction and solid fittings inspire confidence in long-term reliability.Installation was straightforward thanks to the standard 3/4-inch MNPT connection, and it integrated easily with an existing water heater setup. Once installed, it helps manage pressure fluctuations caused by heated water, providing added protection for the plumbing system and extending the life of connected components.Overall, this expansion tank offers dependable performance, quality construction, and an easy installation process. It's a practical upgrade for maintaining a safer and more efficient water heater system. Great value and highly recommended!

[Size: 2.1 Gallon, Number of Items: 1]
I recently purchased one of these type of expansion tanks from the local DIY big box store, so I was able to compare the 2 side by side.The 2 tanks appear to be identical in size and shape, the specifications are identical as to pre-charge, max pressure, temperature,and physical connections, as well as both being lead-free. The one at my local store in the same size was actually 5 dollars cheaper than the present listed price for this one, although I'm sure that price varies from location to location.I guess it's a toss-up as to whether this is the best buy for you, but I can't find any reason not to use it!

[Size: 2.1 Gallon, Number of Items: 1, Size: 2.1 Gallon, Number of Items: 1]
My existing water heaters don't have expansion tanks on them, but expansion tanks really are an important part of installing a water heater properly. Since I'm going to be replacing both of my water heaters, I ordered this Seelink expansion tank to see how it compared to the ones you can find at the big orange DIY box store. I would say that these are pretty comparable to the ones in the store.The tank arrived pre-charged to just over 45 psi (the label says it should be pre-charged to 40 psi, but since I live at a high altitude, that change is probably boosting the pressure in the tank a bit higher than it would be at sea level); you can easily change the pressure in the tank using a standard bicycle pump. It would have been nice if the manufacturer included information on what level of pre-charge are recommended--typically it's the same as your household water pressure. No installation instructions were included in the box. You can find helpful videos online, but the most important thing to note is that you need to adjust the pre-charge pressure in the tank prior to installing it. It's optional, but I highly recommend installing a ball valve between the tank and the water supply line so that you can easily swap out the tank in the future or isolate the tank if it starts to leak and not have to shut off water to the whole house or to the water heater. Because there were no installation instructions, it's not clear whether the manufacturer recommends (or requires) installing the tank in a vertical or horizontal orientation. Most of what I've seen suggests that orienting it vertically with the threaded inlet connection facing down to help avoid having sediment build up inside the tank.The tank is advertised as having a stainless steel fitting where it connects to the water supply line, and based on the minimal magnetism exhibited by the threaded portion of the tank, I believe that to be accurate. The main body of the tank is definitely steel due to the magnetic attraction I observed. The tank I received had some "dirt" inside the threaded fitting--see my photo for the black stuff that came off on my finger when I put it into the inner portion of the fitting. I would have liked to see this arrive cleaner than it did, but I think it'll flush out once installed.I can't comment on the longevity of the tank. Obviously, with a steel tank and it holding water, I would expect corrosion at some point. It's not clear if the inside of the tank is coated to help forestall rusting. Overall, I think this tank is comparable to other expansion tanks I've seen. At the time I ordered this, the purchase price was just over $40. That seems a little high to me since the equivalent expansion tank at the big orange DIY box store (specifically their store brand tank) sells for about $5 less than that. If you don't have easy access to a box store or other supplier, then the convenience of buying this online and having it delivered may make up for that slight price premium.

[Size: 2.1 Gallon, Number of Items: 1, Size: 2.1 Gallon, Number of Items: 1]
Small Expansion Tank Best Suited for Water HeatersI purchased this expansion tank with the intention of using it on a hydronic boiler system, but after seeing it in person I realized it's much smaller than the expansion tank typically used on residential boilers. In the photo, it's shown next to my existing boiler expansion tank for comparison.That said, it's a good size for its intended purpose on a domestic water heater or tankless water heater, especially where installation space is limited. The compact design would fit easily in utility closets or other tight spaces.The tank appears to be well made, with a quality finish, a stainless steel threaded connection, and a standard 3/4-inch fitting that makes installation straightforward. It should do a good job absorbing thermal expansion and reducing stress on plumbing components.Just be sure to size the tank for your application. For a typical water heater, this compact tank should work well. For most hydronic boiler systems, you'll likely need a larger expansion tank based on the system's water volume.

[Size: 2.1 Gallon, Number of Items: 1, Size: 2.1 Gallon, Number of Items: 1]
This is a typical expansion tank for water heaters for residential properties. It has the 3/4" NPT port for connection. This size expansion tank can easily accommodate a 50 Gal water heater. It is easy to install. It is often installed by professionals without support. When it is filled with water, the tank can be heavy. Therefore I l prefer some type of support for the potential weight that it may carry, just assume that the membrane go bad and the tank is fully filled with water, the support needs to carry 2 gal of water in the tank. The tank looks like with very good build quality. The price is fairly reasonable.