Path: utzoo!censor!geac!torsqnt!news-server.csri.toronto.edu!cs.utexas.edu!usc!apple!bionet!hayes.ims.alaska.edu!floyd From: floyd@ims.alaska.edu (Floyd Davidson) Newsgroups: comp.sys.misc Subject: Re: fan question Message-ID: <1990Dec14.160914.9114@ims.alaska.edu> Date: 14 Dec 90 16:09:14 GMT References: <9012130133.AA24147@polar.bowdoin.edu> <6606@suned1.Nswses.Navy.MIL> Distribution: na Organization: University of Alaska, Institute of Marine Science Lines: 36 In article <6606@suned1.Nswses.Navy.MIL> zaft@nswses.navy.mil (Gordon C Zaft) writes: >In article <9012130133.AA24147@polar.bowdoin.edu> poulin@POLAR.BOWDOIN.EDU (Jeff Poulin) writes: >>Here's a dumb little question that I'm not sure of the answer. Which >>direction should the fan be blowing: into the power supply or out of it? >>My computer came configured with the fan blowing in (presumably to keep >>the stuff in the power supply cool), but I noticed the cards become quite >>warm and one of the hard drives starts sounding like a car going 40mph in >>first gear if I leave the computer on for more than 12 hours. Otherwise > > Fans on power supplies should never blow into the cabinet, always >OUT. The idea is to draw cool air into the cabinet, across the cards, >through the power supply and out. > Fans should blow into the cabinet. If the power supply runs hot (not all do, but...) then air flow should be controlled such that the heat goes straight out, not into the rest of the cabinet. There is one simple reason for this. The only effective way to put an air filter in front of the fan is if it blows in. the filter can be directly in front of the fan then. You don't have a filter? Get one. Check this out. Take a look at good quality test equipment, say HP or Weco. 90% of it has the fan blowing in and has a filter. The other 10% is poorly engineered. Floyd -- Floyd L. Davidson floyd@hayes.ims.alaska.edu Salcha, AK 99714 paycheck connection to Alascom, Inc. When I speak for them, one of us will be *out* of business in a hurry.