Has to laugh at the s1 upgrade kit why would ya put all the parts in the kit to upgrade it to an s3 minus the 2nd fan when the s3 has the second fan there for a reason,,,, That very odd and strange not to have the 2nd fan in the upgrade kit
The parts list didn't include the case cover either.
I could cynically suggest that the case cover has cosmetic value only.
The omission of the second fan either demonstrates that the second fan is not really essential, or that Bitmain think that anyone upgrading would have previously overclocked their S1 and would therefore have fitted a second fan already. My vote goes for it being superfluous unless you overclock.
The Bitmain website now includes a fan on the list
I've considered running it without the cover just to see if it helps with the cooling on mine as I can only get it to hash stably at 212.5. My thinking behind this was the location of the control board which is now above the heatsinks and I was wondering if it was overheating, further testing required!