Suggest googling Immersion cooling, there are hundreds if not thousands of threads on doing that for PC and GPUs.  The same rules will apply.

Curious why your looking to do this with your S9s?  The only advantage would be noise since you can't overclock the auto-freq ones, and you would still have to get rid of the heat...

"Highly recommend not connecting directly to the Interent" is an understatement.  Connect directly to the Internet and you will lose control of your miners in minutes.  There, that is more like it.

OK, so regarding remotely controlling your miners, I believe Awesome Miner (www.awesomeminer.com) will allow for that.  I don't use that feature, but do control over 100 miners with AM, and love it.  Patrik, the developer, is great and normally responds to questions within 24 hours.

Cable ties are aptly named...

I'm fond of running 20 amp breakers, so three of those, with (2) miners on each, would be quick, and uses much easier to deal with 12 gauge wire:

Even figuring 1500 watts (14000*0.098/0.93 plus a bit for fans and the controller board) at 220V you only at 6.82 amps.  Of course if you have a 13.5TH instead of a 14TH, they would take proportionally less.

Anyhow, 6.82*2 = 13.64 amps per breaker.  13.64/20 = 68.2%, so doing great there per circuit.

6.82 * 6 total miners = 40.92 / 50 amps = 82%, so pushing that just a bit.

Bottom line, (5) 14TH should be absolutely fine, and you might get away with 6.  (6) 13.5TH boxes should also be fine.

Is the genset going into any sort of normal electrical panel that you then fan off of?  If so, panel surge devices ARE cheap, like $45-$65.  (Well, that is at least cheap relative to the cost of a miner...)

What I had noted when I recently replaced a controller was that it come with 400 Mhz fixed frequency which worked, albeit slowly, with my auto-frequency boards.  Flashing it up with an auto-freq firmware restored normal speeds.  Just not sure an older controller could handle the newer firmer.  MUCH less sure what the fixed frequency boards would think - although that is low risk.  If it failed, so long as the controller wasn't toasted, I could just reflash the fixed firmware.

Really just screwing around exploring these things.

I have a couple of older fixed frequency S9s in my farm, including on 14TH one that is running at 13.6.

I'm just wondering what would happen I loaded one of the auto-freq firmwares?

My guess is that it would boot (controllers likely being compatible), but not find the cards?

Just thought I'd get some opinions before jumping...

FWIW - I've see variable frequency cards do the same thing.  Power cycling sometimes helps... for a little while.

Fully agree with Fanatic26 - these units were never designed for home use.  That said, I had ( running in my basement heating my house for over a year.  If you have an understanding family, its not that bad.  I did use vent filters to quiet down the whinny ones.  Fortunately our TV room was on the 2nd floor.

Oh, regarding CFM through the unit, eg. actual airflow from front to back with the 2 fans combined, I had previously read on the forum that at top speed the fans move about 300 CFM total.

Looks like a classic hash card failure.  Try power cycling (with a minute or so power-off) a time or three and see if it comes back.

My farm has at least 3 different brands of exhaust fans,  all from one batch of miners...  nothing to worry about.

Thanks.

Also need to know what power supply your using if its not an APW3++ being provided 220V power.

Just a sanity check.  I wanted to make sure the Avalon uses the same 6-pin connectors and/or if there was some other surprise reason an APW3++ won't work.

I'm thinking of jumping over to Avalons from my current S9 direction and have well over 20 spare APW3++s.    I know the quality is as good as the Canaan power supply, but would hate to have them just gathering dust.

Agree that you should have a local wallet for any coin your seriously interested in.

Poloniex has been around a long time and has a lot of coins listed.  There are MANY MANY others.

Fortunately control boards are cheap, around $60 USD, but with ridiculous shipping fees and I'm guessing VAT.

Last time I asked Bitmain they told me you can no longer flash firmware via the SD card interface.  Seems strange, but that is what they said.

In any case, if you did brick your unit, yes a replacement controller card would do the trick.  That said, if the units are under warranty, just open a ticket.  Tell them that somehow the unit got bricked while doing a firmware update and that you would like a replacement controller.  They may send you an stock e-mail or two (like telling you to update the firmware first!), just be polite but firm.  Eventually they should let you open a parts replacement ticket after which they will send you a controller within a few days.

In that case, I'd say your having a cooling problem with the hot unit.  It could be:

1) A dead or underperforming fan  (what speeds are being reported?)
2) Dirt on the boards clogging the heatsinks or otherwise obstructing air flow
3) Missing or lose heatsinks

Suggest focusing this conversation on that hot unit for now.

If this unit is still under warranty, you MIGHT violate that by opening the box.  If its not:

A)  Take off the fans and plug them into a fan port on any CPU motherboard and see what happens.
B)  Open the case and pull the hash cards to visually inspect them

Give us more details:

1)  Power supply being used
2)  Voltage being supplied to the power supply
3)  Fan status

Photos are good thanks!

1st photo - air is mixing and the miner on top is eating hot air from the miner below.  Heat rises, so the lower miner gets the cooling room air, the upper miner gets a mix.

2nd photo - back-pressure from the Y.  If you removed the Y and vented both outdoors I think you would achieve your objective.

Agree with Fanatic26.

Please realize that the rating on your transformer is meaningless with regards to the power it can supply, unless you supply it with enough input power.

You have a number of problems:

100' of 14 gauge wire with this load is going to overheat.  Feel the connectors and I bet they are quite warm.  The extension cord your using probably has a label on it telling you its rated for 13amps at most.

I'm actually surprised you didn't pop the breaker on that 15amp 110v circuit.  You might want to check and see what the breaker is rated for.  Hopefully nobody substituted something rated higher (like a 20 amp breaker).  If they did, they created a fire hazard unless the circuit is using 12 gauge (20 amp) wire and the outlet used a down-rated 15 amp receptacle.  Please check the breaker and let us know.  If its actually 20 amp (likely if it was setup for a dedicated refrigerator), take a picture of the receptacle and post that.

Lets assume your pulling 7 amps at 220V... that is 14 amps at 110V presuming a 100% efficient step-up transformer, which it isn't.  A 15 amp 110V circuit should not be continuously loaded at more than 12 amps - thus my surprise the breaker didn't overheat and pop.

Add an AC unit to that circuit and your way overdoing it.

Anyhow, back to my first comment:  5000W at 220V is 22.7 amps.  That transformer should be able to give you that 5000W if you provided it with a 30 amp 110V supply, not a 15 amp one.