What is this piece with the black cap on the connection to my water heater? If I put in a new connection can I remove this? Sorry, the picture is sideways.

Although i don't recognize it specifically, it is on the cold water side of the tank, so it is most likely the shutoff for the cold supply feeding the heater. You don't have to keep that one, and I would change it to a ball valve instead. You do need a shutoff on the cold side of the tank one way or the other.

Do not remove it!! It is a vacuum relief valve that will prevent any negative pressure from affecting your tank. The shut off valve is probably a little bit higher up the pipe.

The flue piping is installed upside down. The crimped ends should be on the "uphill" ends of the pipe and fittings.

Thanks M&M, you are correct and I was mistaken. I looked them up and I have to say.. I suppose in a perfect disaster scenario where you are in a multistory condo with individual water heaters and no form of back flow protection it would make sense…
But I think I would rather bet on the Seattle Mariners to win the World Series in 2015

it also isn't secured with screws

Thanks everybody. I appreciate the responses. I'll keep it as is and just replace some of the piping above all of this.

Thanks for pointing out the flue too. I'll get that fixed.



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it is a watts N-36 vacuum relief valve.
required by code in massachusetts and possibly other areas.

It has nothing to do with backflow prevention. It is to prevent a tank implosion because of severe negative pressure when the cold water supply is shut off to the building and drained.

If there was a check valve in the line it wouldn't be able to siphon, and there wouldn't be any pressure drop

a check valve in the cold water line would then require an expansion tank.
in fact, i believe a check in the cold water feed to a water heater is illegal in MA..