L3+ switch fans, low temps and massive HW errors????

[fyoung55]

Hey guys,
I switched the flow of fans to draw cooler air in from outside, instead of blowing hot air out now that it's getting cooler outside.  The temps dropped way down, like I figured they would, but without changing anything else my HW errors went through the roof.  I'm used to getting 20 - 30 an hour across all boards, but this was kicking out 5 -10 per minute!  Why would that happen?

I switched them back to exhaust the hot air, and my temps and errors went back to normal, but what gives?

[fjzappA]

I switched them back to exhaust the hot air, and my temps and errors went back to normal, but what gives?

Thermodynamics.

Temp sensors are at one end.  Blow cold air onto them they read cool.  The entire system is getting hot, but the system is not aware.

The engineers who design and build these things are not idiots.

[fyoung55]

Does air flow change as well?  I kept the constant 30% fan speed that I always use, so theoretically the machines should be the same temp or cooler regardless of the sensor, as they are drawing 40 degree air instead of 65 degree air.

[imine2]

Does air flow change as well?  I kept the constant 30% fan speed that I always use, so theoretically the machines should be the same temp or cooler regardless of the sensor, as they are drawing 40 degree air instead of 65 degree air.

keep constant airflow 30% fan speed.

Turn them around 180 degree's.
draw in the 40 degree air from where the engineers wan't the air to come in.

see if you get same result.

the answer will tell us all if the people who designed these machines have some thoughts about in which order the different components should be hit by air and if it matters.

I'm interested in the result !!!

[fyoung55]

Yeah, that was my original plan, but my ethernet cables won't reach when I turn the whole machine around.  I'll see if I have some longer ones and see what I get.

[fyoung55]

wow, weird... I did as you suggested and left the fans blowing stock direction and turned the entire miner around, and lo and behold I have same number of hw errors as normal.  They didn't skyrocket like last time... that's crazy.  I guess airflow direction really does matter!

[imine2]

wow, weird... I did as you suggested and left the fans blowing stock direction and turned the entire miner around, and lo and behold I have same number of hw errors as normal.  They didn't skyrocket like last time... that's crazy.  I guess airflow direction really does matter!

Great to know that airflow direction MATTERS ! ! !
Before you had the result I must admit I thought "throughput" (cfm) was most important !

Thanks for the update !

[imine2]

Remember that too cold air from outside vs room air temp can make condensation inside miner happen on the hashboards so don't go crazy with to much cold air.