is it possible to run the unit with a fan ? I have a really cold environment or would it not boot up ?
You mean without a fan? It would run but it would probably be very slow and would restart alot and be unreliable.
You need to move air over the heatsinks to remove the heat. If you have very cold air (sub 10°C you could use a slower quiet fan around 90CFM) You could probably even use the fan on the outside of the miner. I'd want to test it thats for sure. But I doubt you would get anywhere near 1.7TH