On Monday, June 5, 2017 at 12:00:23 PM UTC-4, wrote:
Since this involves metal plumbing I figger it's probably OK to post
my questions.
Advice anyone?
Thanks,
Eric

I have thought about this, but have never gotten around to doing anything.

My thought is to have a switch in each upstairs bathroom that would run the recirculate pump They would be wire the same as a three way switch so the pump could be turned on and off from either bathroom.

Thus would not be a automatic set up. If one was about to use hot water , one would turn on the pump for a minute or so before using the hot water.

Dan