On Sep 11, 1:07*pm, John Gregory
wrote:
I have tweaked this formula to this point

=SUMPRODUCT((Zone=B8)*(O2scfm0), O2scfm)

and it works for the first few cells I want a sum in. It does not want to
calc the remainder of the range (Zone). I completed about 30 zones on my Room
Data tab, and went back to see if it worked, but it did the first few rows
correctly then nothing below that, why?

Do you want it to always look at B8? If you do then you shoudl put $B
$8 instead of B8.
I woudl also change your formula to =SUMPRODUCT((Zone=$B$8)*(O2scfm0)
* (O2scfm)) but that is just me.
Thanks,
Jay