Hi Baha Man,
First off, you are welcome, glad to share to help the cause.
It looks like 2 fans at the top with your control system is working. Some fine tuning will come as you use it. Looks good.
The only thing I will add to think about, not sure if the cover is on the roof vent during your tests, I suspect the the cover being off or on changes the air flow dynamics. The cover is a restriction.
If you have not had the cover on, see how it fits with the fans. If you are not getting enough air flow, part of it "might" be that the cover is too close to the fan and is choking the fans output. The fan blowing out with no cover, has zero restriction on the exhaust end.
You may be able to adjust for the lost volume with speed, waste some speed to get the wanted end result. Or if you run out of speed, then moving the fans below the screen and deeper into the opening may shift the lost efficiencies of being choked being so close to the cover. Mine are about 3" below the screen.
I'm using a Camco vent cover in place of the Dometic. The insides of those two covers are very different, at least by looks. I have no data to say which is better, just Dometic wants way to much $$ for a replacement cover. I do like the Camco for helping to keep sideways blowing rain out of the fridge though. This wind driven rain has to be just right to be head on into the side of the cover to show up, but it is possible as you can see by eye straight through the Dometic, or the older ones anyway. I really do not like the new redesigned ones that they are forcing a base change to even use. The molding quality is poor compared to what they use to make. Dometic is not the same company with higher quality as it used to be 10 years ago from what I have seen.
Thanks
John
