thermal expansion tank

Background: My house is a new build, currently two years old. Last year, I measured the PSI from the expansion tank without any issues. Recently, out of curiosity, I tried to get a PSI reading again but this time a small amount of a sticky, clear fluid (possibly sealant) slowly leaked from the...

I just had my 40 gal water heater replaced. On its first heating cycle, the pressure release line squirted out 1-2 cups of water. I opened the manual, and on page 6 was a giant warning about thermal expansion tanks being required in the presence of a backflow preventer (which my building does...

I installed an A.O. Smith water heater with a friend (handier than me) a few weeks back. There's intermittent leaking at the T/P valve, and I'm confident that I need to install an expansion tank (the old heater had one, but it is not reusable). My question is whether I can work with the flex...

Hi all, I recently moved into a new house (built in 2016). I found a thermal expansion tank in an attic space above the garage. The valve to the tank is closed (see pic below). Shouldn't it be open? Not sure if it matters, but the house has tankless gas heater. Thanks in advance! Alex