I want to make sure I understand you.A, B, C, and D are fine.
E, F, and G can be simplified to remove the risk of dead heading the plumbing with a 3 way valve at E & G and a check valve at F. See Heater Bypass - Further Reading
A three-way valve at the arrow.
Where do I put the second three-way valve at G?
Thanks for your help!
