Rotax 912 pump bypass

Thank you Douglas and Roger. Which pump did you do your experiments with? The Pierburg / old type or newest type Italian mechanical fuel pump?

I will replace my leaking 912 mechanical pump with the newest type pump (with drain line) tomorrow. I got 2 andair check valves, one to bypass the electric pump as the installation manual shows, and another to bypass the mechanical pump as I saw other aircraft fuel diagrams with redundant parallel systems doing this..

I was surprised to find your posts this morning, I had just been discussing it with a friend that told me the mechanical pump bypass & valve was unnecessary. I am now considering to not install the mechanical pump bypass.. but is it not safer to have one anyway? Or is it too complicated and could cause problem?