This article includes detailed information on the Flo Smart Water Monitor and Shutoff, also known as the Flo by Moen Water Shutoff.
Re-circulation systems should not have any issues provided the return branch connects downstream of the Flo Smart Water Monitor and Shutoff.
In the event of a leak on your home’s hot water line, where a re-circulating pump is present and no water is flowing through the pump, the pump may encounter some damage. Some re-circulating pumps will turn themselves off if there is no water in the line to prevent overheating and damage. Please refer to your re-circulating pump’s manual or guide to see if has this feature.