Better temps with inverted airflow on Antminer S9 ?

[ANTZ25]

I'm going to explain the situation;

Because of the config of the rack where  I have my miners (with the cables on the back -hot aisle-)
when I got my S9's I inverted the fans of the miner effectively changing the airflow direction,
and they have been operating in that configuration for a few months now, this are the temps I get:


https://i.imgur.com/xCZ1Gwt.jpg



now, I decide to finally take care of the cable config of my rack, and proceed and reverse the
fans config off the first S9, this is what happen:


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


as you can see there's a 15-16° difference between the 2 settings, anybody has try this?? I thought maybe
the temp sensor is closer to one fan in one config and maybe that's why, but the difference is also
on the chip temp reading, I assume the chip temp sensor is embedded within the hashing chip like most PC's CPU's,
so the temp reading have to be accurate.

any thoughts on this?

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[VirosaGITS]

I doubt, the sensors have been its own chip on the board in the past, not embedded at all. Switching the airflow only changed the readings because the chip was getting less backdraft. Since you're describing the same results and conditions as older antminers, it would be safe to assume its the same effect occurring.

Might be a good idea to buy a cheap digital/laser thermometer.

[philipma1957]

the fins are tight and pretty terrible for straightness  so inverted fans could help.

I would test the exhaust air temp  at the exhaust fan see if it it also lower.

if so you probably do have an improvement.

btw 20 minutes is next to worthless time for an s-9 screen shot.

try 2 or 3 hours not 18 to 20 minutes

[solarismedic]

I'm going to explain the situation;

Because of the config of the rack where  I have my miners (with the cables on the back -hot aisle-)
when I got my S9's I inverted the fans of the miner effectively changing the airflow direction...

any thoughts on this?

Any update on this?  Interested in doing the same thing...

[SGMPhil]

I would be interested to see how this works out as well. My guess is that what is happening is that the temperature sensors are not getting an accurate reading since they are reading air temperatures at the air intake now instead of exhaust so the air heated by the ASIC chips is not being read by the sensor chips now.

[ANTZ25]

I would be interested to see how this works out as well. My guess is that what is happening is that the temperature sensors are not getting an accurate reading since they are reading air temperatures at the air intake now instead of exhaust so the air heated by the ASIC chips is not being read by the sensor chips now.

yes, but the thing is, the temp sensors on the ASIC chips (which i guess are embed in the chip, nobody really knows) also report lower temps.

[ANTZ25]

I'm going to explain the situation;

Because of the config of the rack where  I have my miners (with the cables on the back -hot aisle-)
when I got my S9's I inverted the fans of the miner effectively changing the airflow direction...

any thoughts on this?

Any update on this?  Interested in doing the same thing...

not mining anymore, except for a couple gpu's, into trading and hodling now. While they were inverted they worked fine.