This expansion tank is probably too heavy for the plumbing.
This brand new house is fitted with the plastic CPVC plumbing.
It's fine material, when installed right, and has been used around here in residential construction for about 20 years.
But, it is plastic. It does not have the same strength as does copper.
Being plastic it does not like to have air in the pipes which can create a hammer effect.
But also, when it gets hot and expands too much pressure can be put on the system.
So an expansion tank is installed to help with those two possibilities.
The expansion tank in the photo obviously has a lot of water in it as it is bending down the plumbing it is resting on.
Over time that will not bode well for the plumbing. There are three joints within inches of where it attaches to the horizontal tubing below and any of those could crack and spring a leak in short order.
My recommendation: that tank needs to be lifted a bit and supported to prevent its pushing downward onto the plumbing below, which right now is holding the entirety of the weight. We'll see what happens. Better to handle this now than a flood in the future! A break in plumbing that size would fill the basement quickly! The old motto: better proactive than reactive works very well here.
Jay Markanich Real Estate Inspections, LLC
Based in Bristow, serving all of Northern Virginia.
Office (703) 330-6388 Cell (703) 585-7560