Best method of sequencing Kaeser compressors

Our facility in Indiana has 5 Kaeser compressors total.

We have a 330HP, a 185HP and 3 x 125HP.

We're trying to understand the best way to sequence them.

We typically depend on the 330HP to "lead" and then turn on smaller compressors as the demand increases (pressure switch settings on each compressor).

However, we're not sure this is the best, most cost effective method?

TI Automotive,
Ashley Indiana
Brian, I am happy to post this for you in the hope some engineering types comment for you.

How you are sequencing the compressors is how I would if I were setting them up.

I can't speak to the cost, at least from the perspective of energy cost.

I can speak to the sequencing cost in that, if you lead with the 330 HP all the time, then it is going to be the longest running, and ultimately, will be the one to fail and require maintenance most often.

Consider, if it makes sense to you, changing out, via the pressure switch settings, which compressor is the lead.

Another way would be to have all compressors with the same cut in and cut out, and use a pressure sensor to fire up relays to start additional air compressors as the mains pressure dropped below the pressure sensor sent point due to increased demand.

The good folks at Kaeser would be pleased to hear from you too, I expect. They have got lots of folks on staff that help with this sort of thing.



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Jul 17, 2013
Carl's right
by: Kaeser tecnichian in Scandinavia

Hey Brian
I say the same as Carl, you should get a SAM (Sigma air manager) to run your compressors. Which kind of SAM depends on which type of controls that your compressors have, but propabely at least SAM 8/4 (duno if the model names are the same in the US though)
With such huge compressors that you got it aint no idea being pennywise, i'm sure that a SAM installation would have payed itself within a really short time.
It's possible to program sequencing quite well without a SAM too, but then you need to present more info like average air demand, peaks, how many hours does the top/bottom demand last, are any of the compressors frequency controlled etc.
Rule of the thumb though should be to get rid of as much offload time as possible, especially on you biggest machines, they should preferribly either run as near 100% or be shut down.

Get a SAM and it will save you a lot of money.

/Kaeser tecnichian in Scandinavia (sorry for my poor English)

Apr 25, 2013
by: Carl

Hi Brian,

Which Kaesar compressor model numbers do you have? Or more importantly which controllers do you have on each compressor?

You will normally see it on the back of your controller, either SIGMA BASIC or SIGMA CONTROL 2 or something like that, it should look something like one of these :

Or you may just have on and off buttons or a toggle type which may just have the Kaesar controller (little black square box with 4 LED lights)

Using the pressure switch settings (if set correctly) is a good way of doing it but there is a more energy efficient way of setting them up, although it does mean using a purpose made sequencer or controller, called a SAM (Sigma Air Manager) where, when set up, it controls your compressors to the most energy efficient set up.

These are quite expensive but the energy saving costs are fantastic. Heres some info on them

There is also a MAC 41 which is also compatible with Kaesar compressors, i have manuals for both of these controllers.

Like i say, depending on the age and which controllers you have on your individual compressors, depends on which you need.
I have lots of info regarding this, so if you could find out what controllers you have let me know by emailing me if you like? Im not a salesman, so not trying to sell you anything.
Hope this helps a little

Carl, thanks, as always for your expert advice. If it were possible, it would be best for Brian and folks to respond as a comment here, as then, all info is available for all visitors to the site. I've left your email address in the post and wonder if you get a response from Brian or others, could you add it (them) here as a comment so that all can see it?



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Setting Kaeser pressure switch?

by bob
(tampa fl. usa)

Kaeser SX6 compressor (photo:

Kaeser SX6 compressor (photo:

OUR kaeser SX6 pressure is factory set at 125 psi we now have equipment that requires 150 psi so we need to bump up our tank pressure to 150 psi. Im trying to not get Kaeser techs involved they are expensive may someone know how to set the pressure switch?
Hi Bob... I'm happy to post this for you, but I have my reservations about what you want to do in increasing the pressure output from your Kaeser air compressor.

If you drive a car that is rated at 100 MPH, and without making engineering and mechanical changes to re-rate it to drive at 120 MPH, then trying to drive it at 120 MPH could destroy the car.

Could that happen to your Kaeser compressor if you turn up the pressure setting so that the compressor is trying to compress air at pressure levels outside of it's engineering and material design? I think that could happen.

There is information on this site about pressure switches that you may find useful in your endeavor, though, it were my air compressor, I wouldn't do it.



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Oct 25, 2012
Changing the pressure on the Kaeser SX6
by: MArk Shawyer

On the Kaeser SX6 compressor, you can raise the pressure all the way up to 200 + psi. It does require your to purchase the proper kit from a Kaeser dealer. The kit will have the pulley,belts and pressure switch to make the conversion.Remember the higher the pressure the lower the CFM.

Quad-State Air Compressors
Your friendly Kaeser dealer

Oct 18, 2012
by: Anonymous

the only thing that might happen is that the motor will be overloaded and maybe blow some fuses or the built in overload protection.

To do it right, you should swap one of the pulleys (i never remember if its the motor pulley or the screw pulley, the bolt for the screw pulley is sometimes left-threaded btw, good to know if you are to remove it) and the belt. Check the safety valve on your separator tank, you might have to replace it if it's opening pressure is below 150 psi.

All the components are the same, the only things that differs in the factory beetween different pressure models are one of the pulleys, belt, pressure gauge and sometimes the safety valve.

You should be aware that the pulley swap will decrease the air flow. I don't know the american measurements of air flow, but the european 50 Hz version of an 7,5 bar SX 6 delivers about 550-600 liters per minute, and the 10 bar version delivers about 450 liters/min. You do the math. ;) /kaeser mechanic in scandinavia
Thank you, kaeser mechanic in scandinavia! We all appreciate your guidance.


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water in sx6 oil seperetor

by Robert Smith
(Tampa, Fl. U.S.A)

I have an sx6 unit that had milky white oil, "water in the oil". I removed all the plumming, the oil seperetor and the dryer. I cleaned everything and reinstalled. I then installed NEW oil and filterS.
The compressior runs great with great pressure. The problem is that the oil in the sight glass of the oil seperetor is milky white again,"water in the oil seperetor" What could be causing this?????

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Nov 25, 2013
Strange one
by: Carls421

Just to confirm, the compressor is running at a constant 80ish degrees when running. That is perfect running temperature, so that should rule that out.

You've replaced the oil filter, air filter and put new compressor grade mineral oil in after draining the system of old oil.

Youre still getting milky oil in the seperator tank where you fill the oil inside the compressor where you look through the sight glass.

There is another filter inside the seperator tank that can be replaced but ive never known this to cause milky oil? Usually if that fails then you find that either oil goes into your system (found in either the receiver or oil/water seperator where the condensate goes (from the receiver or inline filters))
Or it blocks and you find the safety valve on the seperator tank pops.

The only thing i can think of at the moment is that the MPV (minimum pressure valve) could be sticking open slightly, letting condensate back through and into the separator tank? Is the oil level increasing? But that is quite unlikely because if it does stick open, you would have a problem of the air taking a very long time to get to the correct pressure.

Like i said in my first message, there are only a couple of things that will cause the oil to emulsify are compressor low running temperature, incorrect oil or oil past its life.

But if you havent changed your oil separator filter, it is worth doing.

Please let me know how you get on. Id love to know.


Nov 25, 2013
oil in water
by: Anonymous

I have rechecked and it is oil and water for sure. It has been in the mid 80s, so not sure if the tempeture is the problem. It never befor made the milk as I call it. Is there something I can do to increase the running tempeture, or could there be a failure with the oil/air seperetor???

Nov 21, 2013
by: Carls421

Just a couple of things to ask you.
When you say you have water in the oil, is this in the oil water separator or the seperator tank? (Where you look through the sight glass) if the sight glass then are you looking at the oil whilst your machine is running or shortly after it has been running? Some do make this common mistake. In that tank where the oil is, the compressed air is also in the same tank whilst running, the air is then passed through the oil seperator filter and out to your system. So as you have compressed air and oil in that tank, it mixes, causing tiny little bubbles in the sight glass, this can look like milky oil from a short distance away, look closer and make sure you arnt looking at the bubbles. The best time to check your oil is before you start it up in the morning.
If it is actually milky then it probably isnt getting to the optimum temperature whilst running in the day i.e. Not running for long enough to get to between 70- 85 degrees, causing moisture to attract to the oil and emulsifying.
Have a check of the above and please reply to this message
Hope this helps


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Compressor Squeals

by Chad Fuglseth
(West Fargo, ND)

When it is building pressure it seems to sound normal but when it is not building pressure and the fan is spinning with out a load on it, it seems like it speeds up and makes a very high pitched squeal or whistle. Can you get different fan blades for the Kaeser?
Chad, that's an engineering issue, and you probably want to get the straight goods from Kaeser:

What is squealing, though?

I don't know what model you have, so I can't even check to see what's what.

However, I worked in a plant with a 25HP demand type rotary screw air compressor, and the sucker was squealing all the time it was running, so this may not, and I emphasize MAY not, be an issue.

Kaeser is your best bet, unless another reader has had an experience with this and wants to offer advice.



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