AvalonMiner 841 temperature issue

[NCDiesel]

So my machines have been happily hashing for a few hours now, and my hash rate has been very good. Looking like about 5% above the specs averaged across the machines. However the temperature has me concerned. The fans  maxed out at 100% nearly immediately upon beginning hashing and I have temperatures in the low 80s (F) according to the controller. Ambient temperatures in the shop are around 70F  So it seems it should be able to keep the temps down.  The shop is an open design, it is 1200 ft.², has 10’ ceilings, and has lots of metal and concrete in it to act as a heat sink.

Can you folks take a look at this image and let me know what you think? Should I be concerned about the temperatures?

http://imgur.com/1mo3EyX

Thanks!

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[philipma1957]

So my machines have been happily hashing for a few hours now, and my hash rate has been very good. Looking like about 5% above the specs averaged across the machines. However the temperature has me concerned. The fans  maxed out at 100% nearly immediately upon beginning hashing and I have temperatures in the low 80s (F) according to the controller. Ambient temperatures in the shop are around 70F  So it seems it should be able to keep the temps down.  The shop is an open design, it is 1200 ft.², has 10’ ceilings, and has lots of metal and concrete in it to act as a heat sink.

Can you folks take a look at this image and let me know what you think? Should I be concerned about the temperatures?

http://imgur.com/1mo3EyX

Thanks!

er

Look to see if they creep to over 88.

A day or two before you know if you are too hot.

You are burning 5200 watts that is about 20000 btu

My garage is 600 sq ft after a week the concrete does get warm

[Steamtyme]

Looking at your fan intake temperature it looks like your shop is a little warm to begin with. The specs call for intake air temp of 30C ad the high.

You also might be short circuiting the exhaust air to the intake. You might need to look at a better way to exhaust the heat or atleast circulate the air throughout the shop.

[NotFuzzyWarm]

The miners and PSU's can be on any side you want and also be packed together if desired. The fans are what do the cooling - not the exposed sides of the metal cases.

Personally, usually I never care about shut down but to prevent heat soak, just kill the pi or disconnect the data cable to the miner. It will go into idle mode with the fans running and you can then power down after they cool off.

[fanatic26]

To me your machines temps are perfect. I dont know what you are talking about worry about them getting hot?

My 741 in a 30f environment run 27c/88c on average. The machine wont even downclock until they are over 100c.

Your intake temps are a little high but the chip temps are just fine.

[Steamtyme]

Just a note the specs are different from the 741 to the 841.

Safe operating temp was up to 40C for the 741's

The 841's say up to 30C for the ambient air temp.

So there are differences to be aware of with the new equipment.

[ccgllc]

For what its worth, I use Bitmain APW3++ power supplies for my 841s (mostly because I seriously overbought them).  I have them on top at a bit of an angle - aligning the APW3++ angled edge to the power connector side of the 841s - it almost looks like they were designed to do that (eg.  Its aesthetically pleasing)

[ruinous]

Your temps seem fine. My "hobby" home rack (in garage) is four miners with two 821's and usually sits 33/78 max overnight. Have had zero issues with hash over 23 th/s together. I don't have much for cooling besides a high velocity floor fan and 300 something CFM household exhaust fan with the garage door a little raised. For summer I'll monitor temps more maybe shut down on the few hot days my region gets if I need to.

[Raymond_B]

Ive determined my problem is all ambient temps(moving the power supplies helped a bit).   We had 2-3 days above average in terms of temps.  A nice cold front moved through and we are in the 40s and dropping fast.   So I opened the shop up completely for a few hours and clearly the temps moderated. 

I think this means I need to exhaust the miners to the outside when summer comes.

https://imgur.com/a/YfiY9

Thanks,

Yes, you'll be amazed at the effect on miner temps by getting the waste heat out. People tend to want to cool the miners, but the key is simply getting that hot air away from them.

[NotFuzzyWarm]

Do NOT start ducting the miners exhaust without using a booster fan and/or larger dia tube. They are designed assuming free airflow in and out of their casings and have little margin for pushing the air against added resistance.

What I used are these https://www.globalindustrial.com/searchResult?searchBox=&q=ventilators to suck the hot air out of the area where my farm is and ran the other end of the pressure duct to a much cooler area of our shop floor. Specifically I use https://www.globalindustrial.com/p/hvac/fans/blower/global-portable-ventilation-fan-16-with-32-flexible-ducting  which moves over 2,800CFM. The bank of miners are pointed at the blower inlet about 10ft away from them.
 

[Raymond_B]

Do NOT start ducting the miners exhaust without using a booster fan and/or larger dia tube. They are designed assuming free airflow in and out of their casings and have little margin for pushing the air against added resistance.

What I used are these https://www.globalindustrial.com/searchResult?searchBox=&q=ventilators to suck the hot air out of the area where my farm is and ran the other end of the pressure duct to a much cooler area of our shop floor. Specifically I use https://www.globalindustrial.com/p/hvac/fans/blower/global-portable-ventilation-fan-16-with-32-flexible-ducting  which moves over 2,800CFM. The bank of miners are pointed at the blower inlet about 10ft away from them.

[...]

Is that an Avalon specific issue? Or simply a concern for the length of the run?

I've had great success with ducting my 2 S9s, 1 S7, and 2M3s

Here is what I did, granted the runs are MUCH shorter, but they do have some sharp bends.

https://bitcointalk.org/index.php?topic=2796117.0


Moderator's note: This post was edited by frodocooper to trim the quote from NotFuzzyWarm.

[ruinous]

The more of the heat you can keep away you'll have more flexibility with ambient temperature to. Of course still watch temps and it's not ideal to experiment with how hot you can get these things, but you could probably operate in 50c temps and still have an 80c deg or less exit even on a tight budget just a good plan to pull the air in/out of room (or from machines directly it sounds like). A lot of it is sort of common sense after you stand and evaluate you set up for a while, like positioning exit like NotFuzzyWarm. I might browse some of the threads on layouts and pics of mining operations for some inspiration.

[ccgllc]

One more question:   The minimum fan percentage that my installation of the controller firmware defaulted to was 100%.   The mini-documentation beside the field on the page says the default value is 10% but it burnt into my controller with 100%.

So my fans my on 4 841 miners run full blast constantly, even on these cool nights where chip temps are in the 50/60C range.  Should I change it to the default so I will get variable fan control?  Or did Canaan realize these 841s need 100% fan all the time?

Thanks again!

You can change the minimum, I did.