Fanless PSU in MicroATX case?

Discussion in 'Overclocking & Cooling' started by PinPickles, Jul 4, 2019.

  1. PinPickles

    PinPickles n00b

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    Hey guys.

    I have a fanless SeaSonic PSU I want to put in a Cooler Master NR400 case.

    Would it be better to mount it with the vent facing up towards the baffle, or upside down with the vent open toward the case vent in the bottom? (See pictures.) There's only about 0.5cm of airspace between the vent and the baffle facing upwards.

    Thanks.
     

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    Last edited: Jul 4, 2019
  2. doyll

    doyll Kyle's Thermocouple is HOT

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    I always mount PSUs with vent to bottom over case bottom vent. Thist way air comes in bottom and flows out back of PSU. Only time this can be a problem is on deep soft carpet that case feet sink into with carpet blocking airflow to bottom vents.
     
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  3. PinPickles

    PinPickles n00b

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    Thanks. The PSU says clearly to mount it with the vent facing UP though. Do you think that'd mess up anything mounting it upside down?
     
  4. ryan_975

    ryan_975 [H]ardForum Junkie

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    Fanless PSU's rely on natural convection and/or induction/expulsion of air from the other fans in the case. Mounting them vent side down would cause them to overheat since there would be no way for hot air to get out.


    *Edited for clarity... again
    I originally said "upside down" this is apparently confusing. It now says "vent side down"
     
    Last edited: Jul 7, 2019
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  5. ryan_975

    ryan_975 [H]ardForum Junkie

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    By upside down I meant upside down from how Seasonic says to mount it.
     
  6. doyll

    doyll Kyle's Thermocouple is HOT

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    So your 'upside down' to mean the opposite of what Seasonic was saying .. so what you said is wrong according to Seasonic. As a passive PSU the vent up is 'right side up' .. while 'upside down' on a passive PSU would be with vent on bottom. ;)
     
  7. ryan_975

    ryan_975 [H]ardForum Junkie

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    There is nothing wrong about what I said.
     
  8. doyll

    doyll Kyle's Thermocouple is HOT

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    Seasonic does not agree with your opinion. Which is the opinion I had before seeing what Seasonic says to do. I trust what Seasonic says, so next passive PSU I install will be with vent up.
     
  9. ryan_975

    ryan_975 [H]ardForum Junkie

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    Your opinion was to mount PSU vent side down (upside down in this context) unless there's tall carpet. My "opinion" (which wasn't an opinion) explained why that was a bad idea for passive PSU's. They rely on convection for cooling... in other words hot air rising pulling in cooler air in under it. So they need the vent facing up... just as a Seasonic says to mount it.

    The problem in the OP's case is that there's a plate above the PSU location that could block that vent. I think in this situation a passive PSU isn't a good idea (<-- that is an opinion)
     
    Last edited: Jul 7, 2019
  10. doyll

    doyll Kyle's Thermocouple is HOT

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    You are correct about case's PSU divider blocking airflow. So I'm back to same as you, PSU vent at bottom of case with plenty fo clearance between csae bottom and what it's setting on. I usually use open center caster bases with 30mm casters so have 35mmm + gap between case/caster base bottom and floor.
     
  11. ryan_975

    ryan_975 [H]ardForum Junkie

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    I never said vent at the bottom. That is just as bad or worse than blocking the vent since there's still nowhere for the heat to go.
    My suggestion is to either get a case that is more appropriate for a passive PSU, or get another PSU that has a fan.
     
  12. doyll

    doyll Kyle's Thermocouple is HOT

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    You've said so many things in wording that is hard to understand .. like what is "Mounting them upside vent side down" supposed to mean?

    I don't agree.

    Blocking full top vent area of passiveve PSU with case's PSU cover shroud would limit PSU venting to it's back vent ara and tiny area on front by cable sockets.

    Mounting with vent at bottom over case's PSU vent should allow the heating of air inside of PSU to flow out through PSU's front and rear venting and be replaced by air coming in the bottom. This is how my semi-passive PSU works at lower loads. Fan does not turn on unless CPU and/or GPU are pulling lots of power at full load.

    As for your 'opinion' not being an opinion .. sorry, but what a persons thinks is their opinion. It does not become fact until supporting evidence backs it up .. and even then it is still an opinion supported by facts.
     
    Last edited: Jul 7, 2019
  13. pitingres

    pitingres [H]Lite

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    OP: Mount it the way Seasonic tells you to, or it will likely overheat. The PSU shroud is perforated in the area that covers the PSU, right? If not, if it's a solid shroud, DO NOT use that case and PSU combo.

    Fanless PSU's aren't semi-passive fanned PSU's and have somewhat different internal heat-sinking.
     
  14. EnderW

    EnderW [H]ardForum Junkie

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    On a side note, what a terrible combination of products and ideas. Fanless PSU in a black interior case with PSU shroud. (No offense to the OP)

    PSUs should never be fanless unless you’re going for some kind of 0dB system. I haven’t seen a PSU that contributes to the overall noise of a system since the PCP&C TurboCool models.

    Cases with PSU shrouds are a terrible idea pandering to noobs that can’t or are too lazy to do any wire management (change my opinion).
    “Let’s just put a plate over everything and cram all the wires were they can’t be seen.”
    I made the mistake of buying a case with a PSU shroud once and what an absolute exercise in frustration trying to do any cable management in that cramped, dark space.

    On an even more off topic tangent, anyone else remember when black case interiors were a premium feature or mod? Now every case has them. I used to think they were cool too until I got one and realized you have to work directly under a lamp to be able to see what you’re doing.
     
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  15. doyll

    doyll Kyle's Thermocouple is HOT

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    I agree about case with PSU shroud and passivev cooing PSU being a horrible combination, but color of case makes no difference .. unless you set your black cased system in the sun without good case airflow.
     
  16. EnderW

    EnderW [H]ardForum Junkie

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    Not a difference in thermal performance, just harder to see what you’re doing without direct light (compared to the “uncolored” aluminum).
     
  17. doyll

    doyll Kyle's Thermocouple is HOT

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    Indeed! Much harder to see things in dark / black cases. My favorite are white or at least white inside. :D
     
  18. honegod

    honegod [H]ardness Supreme

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    Mount it the way the instructions says to.
    The psu uses its generated heat to pump air.
    Mounting it upside down will totally ruin the designed heat/air flow pattern.

    I once built a 'case' with no fans using a 100w lightbulb as the heat source for a thermosyphon.
    Worked fine.

    Flipping that system upside down would have guaranteed overheating.

    I too have a Platinum Fanless running my system because I LIKE thermosyphoning tech.