NO WAY, NO HOW Do I like using a “check valve” on pressure vessel as it is not really a great thing to do.
Considering the fact a pressure vessel has only ONE SAFETY device and ONE operating controller unlike a boiler that has back up systems why take a chance of an explosion?
An expansion tank can take up for the expansion of the heated water when the incoming main pressure increases to the point the T&P discharges and some means of protection is warranted.
The problem today is the use of back flow preventers placed all over the place and thus not allowing for the normal pressure build up of these vessels to move harmlessly into the system.
It always made me curious as to why the ASME allowed the T&P to be rated to a pressure of 150 PSI knowing most plumbing fittings are rated (WHEN NEW) to 125 PSI what is wrong with this picture?
The heat sinks do work and will not restrict pressure release of the tank.
To solely depend on a T&P valve which cost about $4 to protect life and property and also knowing these devices are installed and forgotten until the tank has to be replaced is not what I would consider prudent plumbing.
SylvanLMP Certified Low pressure boiler and unfired pressure vessel inspector ASME section IV