Caleffi Ant-Scald Valve Installation

sibellc

Hello,

I purchased a Caleffi 521 Tankmixer and have a couple of questions. I plan on installing a DHW re-circulation pump. The instructions show two alternate installations. The primary one uses the included cold side coupling, with the recirc line plumbed into it. It has no check valve between the recirc line and the cold supply. There is a check-valve built into the coupling, but it is on the return side to the mixing valve, so would not prevent flow between the recirc line and the cold supply.




Wouldn't this allow for the hot recirc water to enter the cold supply when a cold tap is opened?

The alternate diagram does not use the included cold coupling and does have a check valve between the recirc line and the cold supply.



This is going to be installed by a plumber who prefers sweat connections. I'm thinking I should just not use the included cold side coupling and flex hose, which appears to be more for convenience of homeowner installation, and to install as per the alternate diagram? Or should I use the included part and add a spring check on the cold supply above the coupling? Or will it work properly as detailed in the primary diagram?

Thanks,

Cody