Inverting fans in S15, will it burn?

[euhctcyn]

I got a few S15s yesterday and I was wondering how to attach 3d printed duct adapters, like the ones used in S9s.

I have not come across to any 3D designs yet, since it's a relatively new (and not very popular / too expensive) model I guess, so I was thinking of inverting the two fans, so that they suck and exhaust the heat from inside the miner, instead of pushing the air through the chips. Am I crazy? Probably yes, and that's the main reason I'm here since I'm not an engineer of any kind and I don't want to burn it

I'm afraid that the fans are not designed to suck the air, but to create air pressure to push the air. Just wanted to know your opinion and confirm my bad bad idea. Thanks!

[1714907286]

1714907286

[philipma1957]

run it on lower power setting  normal fan position with no ducts  check temps and fan speed do it for a hour or more

run it on lower power setting with inverted fans and ducts check temps  MY guess is it will work for sure on lower setting. do it for an hour or more

if it works on low setting and temps/fans hardly changed  upward then try higher setting.  My guess is it may not work  on higher setting.

[Artemis3]

Hmm sucking air vs pushing air, which one would keep the boards more cool with the least amount of noise? This is an interesting experiment i'd like to know the results, for science of course

You know in the other side without fans, there is a grill you can take off?

I believe the S11, S15/T15 and S17 will all share the same physical size, someone will build things for them.

[Steamtyme]

Honestly, I wouldn't expect better cooling. Mainly if the fans could cool the chips better with that configuration the machine would have been built that way. Efficiency is the name of the game, and a better cooling design would reduce the work required by the fans, directly contributing to the machines overall efficiency numbers.

I also think that this setup is best unless Bitmain machined new heatsinks similar to what Canaan has had in the past. Pushing the air into the machine and creating that pressure build up through resistance to air flow and heat, pays off on the exhaust side. The air picks up velocity as it leaves the machine back to ambient room pressure.

In the end though, it's your machine and if you want to experiment, go at it slow like Phil suggested.

[philipma1957]

Honestly, I wouldn't expect better cooling. Mainly if the fans could cool the chips better with that configuration the machine would have been built that way. Efficiency is the name of the game, and a better cooling design would reduce the work required by the fans, directly contributing to the machines overall efficiency numbers.

I also think that this setup is best unless Bitmain machined new heatsinks similar to what Canaan has had in the past. Pushing the air into the machine and creating that pressure build up through resistance to air flow and heat, pays off on the exhaust side. The air picks up velocity as it leaves the machine back to ambient room pressure.

In the end though, it's your machine and if you want to experiment, go at it slow like Phil suggested.

If he inverts there is a push fan he can add.

I would need to find the link.

Bitfenix 200mm fan at Newegg can push 148 cfm on the grill side.

And you can invert the two two stock fans  as pull.  It would glow purple led and on low setting I think it would be fairly quiet.

I have cheated with weaker push fans like this on the s7ln as it is not a hot machine.

But I still think only on low power.

The s15 on low setting is well under 1000 watts. In fact close to 920 watts.  It is pretty easy to cool.

I know I have one running as I type.

[Steamtyme]

So running 3 fans instead of 2 with 1 pushing and 2 pulling? Is the push fan mounted directly on the miner, or is the intake ducted with an inline fan? I've just never run/seen this setup before.

If it is 3 fans directly on the miner, would there be an issue with uneven heat distribution, or would the fan cover the entire intake side? I'm just guessing there is another slot on the control board for a fan?

Whatever the configuration it would be interesting to see if there would be any power savings to be had by 3 fans running slower than 2 full out, or enough cooling to run in hotter climates.

Edit: Saw the fan you are talking about. I wonder if some hot spots not in the path of the push fan would form?

[philipma1957]

If  you attach it to the grill as a push it needs a 1/2 inch nylon spacer.  It is a 200mm fan 1 inch thick.

It does not use much power.  It will not fully cover the grill this is why you need the 1/2 inch nylon spacers.

The grill is a rectangle and only two holes in the fan mount get used on a diagonal.

I have a fan I will photo what I mean. Tomorrow morning.

[euhctcyn]

Hmm sucking air vs pushing air, which one would keep the boards more cool with the least amount of noise? This is an interesting experiment i'd like to know the results, for science of course

You know in the other side without fans, there is a grill you can take off?

I believe the S11, S15/T15 and S17 will all share the same physical size, someone will build things for them.

In my situation, since everyone has different setups and needs, I don't really care much about noise. And yes I can remove the grill, but still would need something to attach there so I can connect the ducts. About the same size, the metal enclosure that house the hash board has the same size, BUT I'm noticing few differences in the grill design and screws position for example between the last batch of S15 and the older one (attached pic, new batch is on top). Not sure if there is any difference between S11/T15 and S15.

https://i.imgur.com/DjE4MO5.jpg

The main issue I'm trying to solve is that right now I'm unable to properly remove the hot air from the room. Because of the room design (no natural ventilation nor windows), the system has been running for the past 2 years (with S9s) removing the air using ducts attached with 3D printed adapters, so the hot air was thrown to a garage through several holes in the wall. This system has allowed me to mine under acceptable temperatures but right now the S15s are throwing the air directly to the wall, and temps are getting higher. Right now the miners are taking air that is warmer than it should, since it's not properly removed from the room; I'm in a heat vicious cycle.

Honestly, I wouldn't expect better cooling. Mainly if the fans could cool the chips better with that configuration the machine would have been built that way. Efficiency is the name of the game, and a better cooling design would reduce the work required by the fans, directly contributing to the machines overall efficiency numbers.

I also think that this setup is best unless Bitmain machined new heatsinks similar to what Canaan has had in the past. Pushing the air into the machine and creating that pressure build up through resistance to air flow and heat, pays off on the exhaust side. The air picks up velocity as it leaves the machine back to ambient room pressure.

In the end though, it's your machine and if you want to experiment, go at it slow like Phil suggested.

My point with inverting the fans is that I will be able to attach ducts again with the S9s 3D printed adapters and properly remove the hot air from the room, thus lowering ambient temp and (hopefully) cooling the miners. I know that in "normal" ambient conditions inverting them around will not make an improvement in temps, as you said if they were designed this way there must be for a reason

run it on lower power setting  normal fan position with no ducts  check temps and fan speed do it for a hour or more

run it on lower power setting with inverted fans and ducts check temps  MY guess is it will work for sure on lower setting. do it for an hour or more

if it works on low setting and temps/fans hardly changed  upward then try higher setting.  My guess is it may not work  on higher setting.

Right now I'm running them in low power mode to keep things under control. I'll try it this week and let you know.

Thanks for the replies guys!

[Artemis3]

If that is the problem why you don't just use an exhaust fan for the whole room instead? Then you can mechanically suck that hot air into the garage. Put it at a high place in the wall.

Note that if you place them horizontally like that, you are heating the upper board more. Don't do that, the boards should remain vertical.

[euhctcyn]

If that is the problem why you don't just use an exhaust fan for the whole room instead? Then you can mechanically suck that hot air into the garage. Put it at a high place in the wall.

Because for safety reasons / insurance (in case of fire originated in the garage, for example) the garage needs to be isolated from the house, where the miners and all the wiring / installation is done.

So originally I had 12 x S9s, and I did three 125mm holes in the wall where I was connecting 6 x S9s using ducts, and the other 6 where just throwing air inside the room. Of course there are some industrial fans there to suck the hot air but since now I have 8 x S15s (sold the 12 x S9s) and none of them have their exhausted air being sucked into the garage the fans are not enough to keep everything cool. I really ned a more "direct" way to suck the hot air, and by direct I mean ducting the miners to the 3 holes so that not all the hot air stays in the room.

Note that if you place them horizontally like that, you are heating the upper board more. Don't do that, the boards should remain vertical.

https://imgur.com/a/2rXy6KO

I already noticed that some boards had higher temps than others and that it is mainly due to the horizontal setup, but I'm not sure if at this temp levels is there any danger for the boards. I will take that into consideration and place them vertically, thanks for the feedback  

[mikeywith]

Boards having higher fan than the rest is normal, it has almost nothing with how they are placed, every hashing board performes differently, i tried re-positioning some boards on many gears, it never worked.

As far as what you are trying to do, you can pretty much make the 3d duct design your self, a rectangular to round shape converter will work just fine.

[euhctcyn]

Boards having higher fan than the rest is normal, it has almost nothing with how they are placed, every hashing board performes differently, i tried re-positioning some boards on many gears, it never worked.

Will do some more testing to see how it performs best, thanks for sharing your experience!

As far as what you are trying to do, you can pretty much make the 3d duct design your self, a rectangular to round shape converter will work just fine.

Yep, that’s what I’m trying too, I’m reaching people that can print 3D to see if they can do it for me