"thermal expansion relief valve" instead of expansion tank ?

[RustyShackleford]

I've seen for sale a "thermal expansion relief valve", supposed to be a suitable replacement for an expansion tank (on a water heater in a closed plumbing system). Such as: https://www.supplyhouse.com/SharkBi...ER-1-Thermal-Expansion-Relief-Valve-Lead-Free

I'm wondering what knowledgeable people think about these.

I realize you have to provide drainage for the overflow; but you need to do that for the T&P valve already. I don't like that the tank can fail without you really realizing it; I'm not sure how and how often the valves fail. Having to suspend the tank also seems like a hassle, when, for example, the tank is hanging sideways off a tee.

 

[Twowaxhack]

I’ve used them before, they work.

 

[breplum]

They are newish, wacky to me without having spent time looking for product literature. Will do when I have a chance.

 

[RustyShackleford]

They are newish, wacky to me without having spent time looking for product literature. Will do when I have a chance.

Ok, I'l get you started here ...

https://www.sharkbite.com/us/en/bra...control-valves/thermal-expansion-relief-valve

 

[breplum]

Shows you how tired I am tonight.
Saw Graham Nash at a live show in Berkeley, in a wheelchair, from having fractured his hip in three places a few days ago from a fall.
Must have good painkillers, but he is a champ at eighty.