Antminer S9 Static Pressure

[Noface12]

I have search all over the forum and google trying to find the static pressure of the S9. To be more precise, the external static pressure of the exhaust fan.

Everyone talks that it has high static pressure but no one have actually mentioned the spec (mm-H2O or inch-H2O)

Anyone knows the exact data?

[NotFuzzyWarm]

It's not the 'external' static pressure. There is no external or internal about it. Static pressure refers to how much pressure the fan can produce against resistance when it reaches zero airflow. As for the actual rating of the fans used, just search using the manufacturer name and part number on it.

The thing on using high static pressure rated fans is that it applies to both the intake and exhaust fans - the rating can be reversed to imply how much suction the fan can produce. The s9 uses a very densely packed array of heatsinks making it difficult to move air through them so Bitmain just took the brute-force approach to it.

As for measuring just what the pressures actually inside the miner, look up making a tube manometer - very easy to make - is just a length of flexible tubing then measure the pressure.  I've never bothered to actually measure it because no reason to - what BM uses works.

[Noface12]

I know  "Static pressure refers to how much pressure the fan can produce against resistance when it reaches zero airflow"

The ventilation people need to know the static pressure of the fan because they want to calculate if the antminer s9 can push the hot air itself trough the duct and what duct size it needs to be able to do it.

[NotFuzzyWarm]

Rule of thumb when ducting any machine that normally has free air flow in and out, this applies to chillers, air compressors and and other self contained machine using high flow fans such as miners: Every single manufacturer I have worked with always required a powered ducting system rated at a free-flow equal to the machines stated airflow. Failure to do so voids the warranties.

Don't hold me to it but AFAIK for a s9 that is a free flow in & out of around 250 cfm. Considering the fans are already working hard to keep reasonable temps, raising the work load by adding adding resistance (passive ductwork) will only reduce the miner's internal airflow and result in higher chip temps.

[fanatic26]

Ducting into and out of an S9 is usually a bad idea. IF you have to do it, use at least a 6" duct, at 4" there is restriction and overheating.

[Noface12]

Don't hold me to it but AFAIK for a s9 that is a free flow in & out of around 250 cfm. Considering the fans are already working hard to keep reasonable temps, raising the work load by adding adding resistance (passive ductwork) will only reduce the airflow and result in higher chip temps.

I understand what you said and it is logic. I agree with you that putting more work to the fans is bad. The fans are already pushing air out. The idea was to know the pressure to see if that force was enough to push the hot air outside trough a big duct.
 

Ducting into and out of an S9 is usually a bad idea. IF you have to do it, use at least a 6" duct, at 4" there is restriction and overheating.

I am planing to use a big duct, rectangle maybe 24in wide and make the S9 blow the air inside and push it out.
That the reason why I wanted to know the static pressure

[fanatic26]

I have recently done testing on this very thing as we are designing enclosures for our s9s.

As you may or may not know, S9s come with a variety of fans. They all have the same basic specs but in real world testing ill have one s9 moving 180 cfm, and one next to it moving 320 cfm based on the fans. One might have a 1,.6 amp fan, the one next to it might have a 2.6 amp or a 3.3 even. Since all s9s are not created equal the best you can hope for is a weighted average. Most people agree this is in the 225cfm range.

[Noface12]

I asked bitmain about the static pressure and no answer.

I guess I will have to pay a lab to get the info hehe.

[NotFuzzyWarm]

I asked bitmain about the static pressure and no answer.
I guess I will have to pay a lab to get the info hehe.

You have your answers - if you are ducting miners you MUST use a fan/blower at the outlet of the ducts that can move at least the same CFM as the combined miners do. You CANNOT use just the miners themselves to do it. If you just want to ignore what has been said here, sure, go ahead.

[Noface12]

Okey I get it, I need to install extractor at the end of the duct to help exhaust the air outside because the fan it self cannot do it. I was trying to avoid the extractor installation and buying one.

I guess I got no choice unless I find a way to put the back fan of the miners blowing directly outside and the air not returning inside

[ruinous]

Correct you can't avoid using an inline duct fan or what have you. The miners fans are mean to blow air out into "open space" not forced into piping ducts. If you're looking to save coin through expenditure I would look at venting the heat from the ambient air or if you have cut the miners to hot/cold sides from the hot side. alleviating the need for ducting and multiple inline blowers.

my 2 satoshi's.