Solar heating 2 different head sizes


Aug 3, 2018
Hi all, so I bought used some solar panels, ones with 2" and 1 1/2 head. I would like to install all of them... I have a few ideas but not sure... Thoughts on
Install of 2 different sizes heads?

Thought about installing the way the last diagram shows (adding in another bank) where the top bank is 2" and the lower back is 1 1/2


Mod Squad
TFP Expert
LifeTime Supporter
May 19, 2010
Tucson, AZ
I would think you would want to run through the 2" headers first and then the smaller ones. Although if the banks are in parallel it likely does not make any difference.

That bottom picture is fine, although usually you do not need all the isolation valves that they are showing.