What to set Air Compressor pressure cut out switch at?

[Com_VC]

Hi all,

Just wondering what you all have your air compressor cut off switch pressure set up. Mine is currently set to cut out at 150psi. Does this seem a little high?

It is a 3HP 16CFM single phase Belt drive Compressor,

Thanks

 

[OccupantRJ]

I run mine at 120.

 

[Citation]

I would suggest what ever the factory setting was.

 

[Notgrownup]

Mine is set at 150 but I am not sure I can change it.

 

[finn]

I have a Champion and an Ingersol Rand, both 80 gallon tanks, in different buildings, and both factory set at 175 psi.

I lowered them both to 150 psi. They are older pumps, so I figured that working against a lower head pressure will maximize their remaining lifespan. I regulate the distributed power to about 100-120 at the wall, and less, of course, if painting.

 

[larry_g]

My personal opinion is that a single stage compressor should be set to 125-130psi cut out. a two stage should be in the 150-160psi range. Run an experiment; time the progress of the compressor for each 10 psi built in the tank. I.e. how long does it take to go from 100psi to 110 psi. Then time 110 to 120 psi etc. If you find that the last 10 psi is a long time then your cutout is a bit high. A long run with with a small build is making heat, wasting energy, and not getting you where you want to be.

lg
no neat sig line

 

[Bretny]

Kobalt 60gal. Factory set at 155psi. The littlw extra over 120 really wakes up air tools.

 

[sberry]

Leave it alone if that is where it was factory set.

 

[coljar]

My Curtis is set at 150#, which I concider perfect for my needs. The Kellogg-American in the old garage next door is set at 130# which was it's factory setting in 1946 according to the manual.

 

[Tinkerman66]

Mine was set factory at 175. I set to 150 then regulated to 90 in the shop in my PVC airlines. Working great for 20 years now.

 

[maxpat82]

3 hp and 16cfm....I doubt it would be set higher then 120 from factory

 

[sberry]

Many/most singles were 135. I see newer ones at 150. If it works I want all it will get especially for running air tools. This is the advantage of 2 stage, its turning on where single is shutting off. Single runs the tools well enough at the top when its fully charged but down below 120 or so starts falling off due to the fact it doesn't have the headroom for losses thru hosing.

 

[Citation]

When comparing tank capacity I like to look at something like "gallons over 90psi". The idea is tank capacity under 90psi is too low to be useful (that of course depends on your needs).

So consider two compressors, 4 gallon at 130 psi vs 6 at 110. The first is 4*(130-90)=160. The other is 6*(120-90)=120. So in this hypothetical case the 4 gallon compressor had more usable capacity even though the tank is smaller. The extreme case of this is a big tank that tops out at 85 psi is useless if you need 90 psi. It also gives you an idea how much capacity you lose when you cut the pressure down. Consider going from 145 to 130 as the upper cutout. That's a near 30% drop in usable capacity if 90 is your limit. If you consider 90 at the tool and add say 10psi for line loses then you lost 1/3 of your tank capacity with that pressure drop. Of course this isn't an issue if your pump can outrun your tools. It just means more frequent, shorter fill cycles. On the other hand, if you are counting on the tank to save you from a low power pump (my life until I get the garage wiring fixed ) then tank capacity helps.

 

[LS6 Tommy]

MAWP is on the receiver ASME tag. I wouldn't set the operator (pressure switch) much above 80% of MAWP and obviously not higher than the safety valve rating.

Tommy

 

[engineer2]

The Champion factory setting is around 120 to 175 give or take 5 psi.
I have our Champion VR5-8's at work start at 135 and cut out at 165 using a more accurate pressure switch wired in series with the factory mechanical switch.
I could probably lower the cutout pressure more since the plant only wants 105 minimum. No need to pump the compressor up to pressures that are much higher than you need, but too low and your downstream pressure regulator(s) might not work as well and act as a bottleneck in your airflow.

 

[6768rogues]

I use the factory setting. If I were to set it higher, the tank might not be able to take the extra pressure. If I set it lower, it will cycle more, having more start ups. Start ups cause high power usage and more wear, because oil drains to the bottom of the compressor after shut down and has to get distributed after start up. I think the theory that it will last longer if you lower the pressure is BS, it will cause more start up cycles accelerating wear.

 

[matt_i]

I'd set it as low as I could go, consistent with your air flow/pressure needs. That will give you the lowest cost of operation, and longest service life of the compressor.

My philosophy as well. Keep heat down and live a long life. My T-30 is set at 130 psi down from the original 175-ish setting.

 

[bsaint]

Compressor packages are designed to run at a certain RPM and PSI. The lower the PSI, the faster the package should run for maximum efficiency. So if you have a high PSI package, and you run it at a lower PSI, you are actually making less air than if you purchased a lower PSI compressor with the same hp. This is why we don't sell 175# machines to factories needing 115#. The same exact machine but geared for 125# will make more air at 125 PSI than the 175 PSI machine.