I can confirm that you can just add a second fan onto the F1 and it will run just fine. I have done it to 18 of my F1s and it controls the fan and reads rpm properly.
On a side note, you do not need to go the ghetto zip tie route to hold the fan on. If you are taking the plate off and voiding the warranty already you just need to get some of those short fat 120mm fan pc mounting screws (we got ours off of old cointerra fans) and screw them in from the backside. You can only fit 3 of the 4 screws but it is totally stable with no wonky zip ties preventing everything mounting 100% flush
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It should work fine with another fan on it. I am testing "stock" right now but plan on trying a second eventually. So that is in "store" to do. But so far the one fan seems to work fine. It is higher RPM and I have not experienced problems let it running on auto with speed.
