Second Air Compressor or Tank for Relatively Long Distance

[39CAMC]

For some reason, I just can't think through this....

At work, we have the compressor towards the front of the building. We have a long skinny space, 40' w x 150' long.

The compressor is plumbed with (new 4 y.o.) 3/4 iron pipe for the first 25', then I did the back part of the shop with a 3/4 Rapid Air Kit.

My alignment rack and tire machine are down at the far end of the shop/line.

Our compressor turns on at 90 psi and off at 135. It is a 10hp compressor with 120gal tank

The issue is that by the time the compressor kicks on, the pressure loss at the far end of the line has it down to 60-65psi and the tire machine air functions are basically useless at that pressure. The alignment rack jacks are also slow at the low pressure, but they at least work. When this equipment was up front, closer to the compressor, it worked fine as pressure never dropped below 85-90.

We have a second 10hp compressor with an 80 gallon tank and I am trying to decide how to use it to help the problem.

1) Will using the second compressor as a storage tank only, either in the middle of the line or at the back help the pressure drop?

2) Will hooking the 2nd compressor up, either in the middle of the line (preferred) or at the end, help? I don't have 3phase/220 electric down at the end of the line, plus I am trying to stay away from the noise, hence my reluctance to put the 2nd running compressor down there.

2a) What other issues do I create with 2 compressors on the same line?


If both of these ideas ****, I could split the line in the middle, use the existing compressor to feed the front of the shop and then hook up the 2nd one to the back part of the shop, but this is least preferred as we wouldn't mind having two compressors available to work everything in an emergency.

Thoughts?

DaveW

 

[TonyJ]

Why not just bump up the pressure? It coming on at 90 is way two low to still have 90 at the end of a long run like that. I also have a 10hp and I have mine setup at two different pressures 125 on 155 off and 140 on 175 off. Or run a regulator on the front half of the building if that half needs the lower pressure then run your back half at whatever pressure you need also thru a regulator if needed.

 

[TonyJ]

Why not just bump up the pressure? It coming on at 90 is way two low to still have 90 at the end of a long run like that. I also have a 10hp and I have mine setup at two different pressures 125 on 155 off and 140 on 175 off. Or run a regulator on the front half of the building if that half needs the lower pressure then run your back half at whatever pressure you need also thru a regulator if needed.

At 10 hp your compressor should be capable of around 40 cfm or so depending on the compressor so it also should be rated to run at 175psi so check it’s specs before turning it up if that’s an idea you would like to try. This way you only have to adjust its cut on cut off and add a regulator or two if necessary

 

[39CAMC]

I will double check the specs on both compressors tomorrow, I don't think either is capable of more pressure so I might have something wrong with my numbers.

I *thought* the main now is maxed at the 135-ish and I thought the second one was rated 150.

But I might be talking out my %*$*$ on that.

DaveW

 

[larry_g]

I would suggest that you plumb in the second compressor as near the far end as is comfortable. Run with only the receiver in the system. This should alleviate most of your problem caused by line loss over the long distance. If it doesn't then you can power it up. I also agree with the above to run your cut in pressure at 120 psi or so and cut out at 150.

Lastly if you have to run power to the far end to run the compressor consider running an additional set of piping to reduce line loss instead.

lg
no neat sig line

 

[TonyJ]

I will double check the specs on both compressors tomorrow, I don't think either is capable of more pressure so I might have something wrong with my numbers.

I *thought* the main now is maxed at the 135-ish and I thought the second one was rated 150.

But I might be talking out my %*$*$ on that.

DaveW

Yeah maybe post the pump that’s on it if you can’t find it’s info. 10hp is a beast especially if it has a good quality pump. No idea what all you have running that requires the use of air but most 10hp compressors that I’ve seen puts out enough air to supply a neighborhood lol. So maybe get back with us on brand name or actual specs if you have them. If it’s actually 10hp and a good pump that is capable of higher pressures then you can easily keep things the way they are and just bump up the pressure and add regulators if need be

 

[510ebl]

Is increasing the supply pipe diameter from 3/4” to 2” out of the question? You could still add the second storage tank near the equipment if required.

 

[39CAMC]

Is increasing the supply pipe diameter from 3/4” to 2” out of the question? You could still add the second storage tank near the equipment if required.

Not 100% out of the question, but pretty low on my list. We don't own the building and if I don't have to, I don't want to invest in that, especially since I don't really have the stuff to do it myself.

DaveW

 

[imjustdave]

Your basically exhausting to great of a volume of air at the end of a long small line, so your pressure drops like a rock, and then bounces back up when you stop.
The line being small also introduces Resistance. Same principles in power and water.

You will always have lower volume and lower pressure at 125 feet and 3/4 line, once you start to use air.

I suspect if your filling a small tire or basketball the pressure is fairly constant but when you have big demand of air from the machine the pressure drops like a rock then quickly recovers in 5-10 seconds.

You could easily add a storage tank closer to the machines or at the machine, this tank would supply the instant loads and then refill - top off when machines are at rest. The main compressor would run less often but longer as it would have to fill both tanks.

Keep in mind
If the air load is big CFM, Spray painting, air grinder, big volume load once the tank is depleted you're where you are now, with the exception of the tank also has to refill, so recovery will be even slower.

IF you add an additional compressor and connected them your basically adding more sustained volume of air, and raw storage of air, you will have to do some work to make them play nice turn on off ETC.

BUT
Reality is your airline is too small for the demand you have at 140 feet.
Simply plugging in 130PSI and 3/4 line the math says at 15 CFM pressure drops 22 PSI...108 PSI at the end of your line.
Plug in 90 PSI tank pressure and the drops is 14 PSI or 76 PSI at the end of your line,
All of this falls in line with your experience.
Some decent tools here to run the math.
https://www.tlv.com/global/US/calculator/air-pressure-loss-through-piping.html

Run the math on the old line length.... it dropped only 3.5 PSI at 25 feet.

If your line was
1 1/4 to 1 1/2 line the pressure drop is only 1.4 to .6 psi at the same CFM draw.

SO basically the simplest fix is to run a big line down the 140 feet, then branch off with smaller lines.

 

[Jagmandave]

If it's not feasible or easy to increase the pipe size, put a shut off valve partway down, and plumb in the other compressor to run the back half of the shop? That way either compressor can run the shop in an emergency.

 

[nadogail]

In addition to lower flow resistance a larger line will increase your effective tank size.

Adding the second compressser with a valve to isolate the two sections of the air system will also be IMHO, a great way to to improve the delivery of the air you need and also give you an emergency backup.

 

[The Cobbler]

you need to boost the "on" pressure . 90 psi is too low

 

[sberry]

I also would be looking to see why the pressures are set so low. 140 ft of 3/4 should work dandy, , my machine works on that and have 100 ft of 1/2 in my shop, can't tell, runs a 3/4 gun no prob.
I know the charts are calculated but they are super conservative and often seem more speculative than accurate a 3/4 steel is closer to 7/8 than 3/4, have sandplasted 150 c.f. on it.
But for tool system air that machine is turning off about when it shod be turning on. Adding another unit down the line will help a little, if it was marginal a little help might do it but this is the exact reason w stage is used for tools. Don't have to try every scheme ever invented to make up for the wrong compressor.
I am not sure how popular single 10 are, can't re all seeing one any time recent. Take a pic,,, 10 hp is pretty respectable, should easily run that stuff from 3/4. Tire machines do seem to lose a little poop when they get older.
10 were designed to be a one shot deal with this type of shop, aint no way 90 start is right for this type of system running mechanic tools. Already too low before it hits the first foot of pipe. 3/4 is considered right for 30-35 cfm for mechanics. Designed for transmission, the loses somewhat irrelevent if it delivers 120 or better to a secondary regulator.

 

[sberry]

I see the long run is rapid and not pipe. This is adding a little insult as it is tuning size as far as I know. But,, right pressure shouldn't matter and being delivered as low as 65 doesn't make this a mystery, 30 too low this is huge loss.

 

[TonyJ]

I see the long run is rapid and not pipe. This is adding a little insult as it is tuning size as far as I know. But,, right pressure shouldn't matter and being delivered as low as 65 doesn't make this a mystery, 30 too low this is huge loss.

Also the op stated that the compressor Is 120gal so really with the 120gal plus all of the 3/4 line adding a second tank down line isn’t really going to help matters much because the second tank will be having a hard time filling up as tools downstream are using air out the backside. Higher pressure is a must I believe in his case. At 140 on 175 off I can run grinders and cutoff tools at over 200 ft away using only 50ft sections of 3/8 hose coupled together. Efficient at 200ft 3/8 ? Of course not but does it work without slowing down absolutely. So his first place to start checking would be compressor specs and pressure adjustments. If neither compressor will go up to the 175psi then I’d sell both and buy one that will because one good one would be worth allot more than two running at the same time to keep a shop going.

 

[ljhhontx]

My experience lies in natural gas but it's the same principle, I would bet if you would just tie the 2nd tank in at the midway point or back end it wouldn't even need to be on, but you can hook it up electrically later if that doesn't quite solve your volume problem. If you do hook it up to run set to come on at lowest acceptable pressure to start and same cut out.

 

[stonesfan68]

Install the second compressor/tank near the tire machine. Increase the pressure setting of the running compressor to the point where the tire machine works and no more than that. More pressure means more leaks and artificial demand and cycling of the compressor and that leads to a higher energy bill and more compressor repairs.

You should also consider installing a high performance pressure regulator (flow controller) after the primary compressor to act as a firewall between the demand and supply. That keeps the compressor from cycling every time the pressure drops a few pounds and again lowers maintenance and power costs.

This is an example of the type of regulator that I’m talking about- it is not a cheap unit that you can buy from Harbor Freight or Home Depot.

https://www.ingersollrand.com/en-us/air-compressor/products/compressed-air-controls-and-automation/flow-controller-pace.html

However, a higher quality regulator that is less costly would be better than nothing at all. They just tend to have significant pressure drops across the device which defeats the purpose in this application.

Let us know how it works out.

 

[stonesfan68]

In addition to lower flow resistance a larger line will increase your effective tank size.

It seems like a longer pipe would add significantly more volume to the system but it really doesn’t:

120 gallons = 16 ft3

Volume of 3/4 inch pipe at 100 feet length = 0.3 ft3 / 2.2 gallons
Volume of 1 inch pipe at 100 feet length = 0.5 ft3 / 3.7 gallons

 

[redmondjp]

Having the second tank very close to the tire machines should solve this problem. Make sure to plumb it for an easily-operated drain valve as it will collect water.

 

[The Tool Tyrant]

As others have stated, change your pressure switch (if current switch is non-adjustable) to an on @ 140, off @ 175 switch that is if it's a 2 stage pump AND add another receiver at the end of the line. That should surely solve the issue.

 

[39CAMC]

UPDATE

I didn't climb up to the main compressor to get the specs from it, but I am doubting my memory of it being 10hp.

The second compressor is 5hp, not 10. Or even close. Not sure where I pulled the 10hp thing out of the air....at least I have the 120g tank size correct.

Regardless, when I was looking at the second compressor, i thought a little harder and realized that I could easily hook it up at the far end of the line as a receiver tank only.

That far end of the line is where the tire machine is at, FYI.

So, I had all the stuff on hand to cobble a hookup together and drug it down there and hooked it up.

Just using it as a receiver tank seems to have fixed/band-aided the problem. I am keeping 90-95 psi at the tire machine when the compressor starts which is fine.

I realize to properly fix the problem, I realize we need a larger feed line from the compressor, and a higher kickoff and max pressure on the main, but like I said, with only a few years left on this lease, we don't want to replumb and the main compressor is fairly old, so we don't want to max it out unless we have to. If/when it breaks, I will then probably get a 10hp one

Thanks for all the advice and thoughts. I just couldn't wrap my brain around the fluid dynamics of the second tank (and the location being pretty important) but now I have a workable setup and learned enough to know how to keep ahead of future issues.

DaveW

 

[sberry]

You don't need larger feed,, the concept that the pressure is too low here is getting lost,,, is the main comp 1 stage or 2? This is a basic,,, fundamental,,,question. A real possibility of a fix by adjustment. What you did will help some, more tank can be a good thing, its not bad but its kind of backwards trouble shooting.

 

[johnnyradiant]

With the 'storage' tank added you now have more volume to use of low pressure before the pump kicks in. I believe the only way around the low pressure is a switch adjustment. If the gear can operate at 90 psi with a storage tank right there then that to me shows line is too small. Another fix would be to run your main line / trunk line / feed line as a loop rather than a single line with a beginning and an end.

 

[The Tool Tyrant]

Dave, It's important to remember that higher pressure = more usable air volume in your receivers (tanks).
Try to get more info for us on your pump. If your current pressure setting are factory, there is a good chance that it's a single stage pump.

I am a big believer in more storage can make-up for lack of CFM...to a point. Plus it saves your motor from cycling.

 

[39CAMC]

With the 'storage' tank added you now have more volume to use of low pressure before the pump kicks in. I believe the only way around the low pressure is a switch adjustment. If the gear can operate at 90 psi with a storage tank right there then that to me shows line is too small. Another fix would be to run your main line / trunk line / feed line as a loop rather than a single line with a beginning and an end.

90-ish PSI is not a problem for the tire machine, but without the extra tank, it was getting down to 70-ish or below and that was a problem.

Dave, It's important to remember that higher pressure = more usable air volume in your receivers (tanks).
Try to get more info for us on your pump. If your current pressure setting are factory, there is a good chance that it's a single stage pump.

I am a big believer in more storage can make-up for lack of CFM...to a point. Plus it saves your motor from cycling.

I am pretty sure it is 2 stage, but it is up on a mini mezzanine and not terribly easy to access.

When we originally setup the shop when we moved in, the compressor was in the center of things. To the right is "the fab shop" that we sublease space to and they use the most air, especially when using the CNC plasma.

My auto shop stuff was to the left. The lines were short and also 3/4 Rapid Air and it was fine.

Everything worked fine then. We do use a lot of air when we are using it, especially if I am doing tires at the same time as a big CNC cut. But we don't do that all the time, probably not even every day.

Last fall, we got access to a lot more area in the building and I moved my auto shop stuff to the far end of the shop and added the long run but it is tagged onto that original pipe to the fab shop.

So, things could be improved in the piping, and also the pressure and at some point, that old main compressor will die and we will have to do something with a new compressor which would add more pressure. We know I apparently have a thing for 10hp compressors.

Regardless, with the usage pattern we have, I think this receiver tank fix will work for now.

Thanks though for all the continued thoughts, I love to learn more about this.

DaveW

 

[Mr_B]

It be worth taking time look at the on off adjustment potential as that improve it further and save startuo cycles thus help the power bill as well as improve working air supply even further .
even a jump to 105 and 150 do you .
I done 2 air installs in large shops and used twin setup in both as only way get a true good working line pressure and costs within low budgets given .
With flip of lever valves you could easily run on just one and one tank or 1 and 2 tanks during a fault or weekend work with half crew .
I run 2 5hp in my shop, 95% time only need 1 so always covered for a failure or odd big demands .
I'm lucky with my shop as everything pretty central to compressors, larger truck and farm shops I worked in did struggle if using 1 average good install .

 

[908Jim]

Pressure switch should be set above your desired operating pressure. If you have a single stage, which it sounds like, 95-100psi kick on. Essentially, your compressor should be kicking on as line pressure begins to drop so the compressor has time to keep up with demand.

If this is still an issue, I suspect there is a line sizing issue. You should list out your air demand and where the drops are. What would be helpful for us is understanding something like Tire machine at X feet from compressor, alignment rack at Y feet from compressor etc.

 

[Worsedog]

Just as a point of information, the dealership I worked in back in the 80's had an 80x200 shop space that also contained the body shop. It had two 10hp compressors with 250gal tanks. It also was plumbed with a 4" main line with 1" drops to each bay.

Everything in the shop was air powered, the inground lifts, tire machines, the elevator in the parts dept. and even the ventilation fans.

 

[Milton Shaw]

Run a straight line of 1" or so to the end of your present setup. That makes a system a loop and equals out the pressure of the whole system. That does not require removing and replacing the all the drops you now have. The 10 horse compressor should be a two stage with one piston bigger than the other and should be set at 175 or so psi with tanks certified at 200 psi or more. That should be the most affordable and easiest of the fixes that need to be done.

 

[imjustdave]

You don't need larger feed,, the concept that the pressure is too low here is getting lost,,, is the main comp 1 stage or 2? This is a basic,,, fundamental,,,question. A real possibility of a fix by adjustment. What you did will help some, more tank can be a good thing, its not bad but its kind of backwards trouble shooting.

You missing the point of physics, his pipe is too small a diameter for the length based on his air demands.

When he installed a tank the pressures didn't change, but the volume of air is much closer now so it works for him, that is one workable solution, as was upping the size of the pipe.

FYI
it worked before he moved it... so PSI is fine.. and it's working now that he move a considerable amount of air storage closer.

 

[matt_i]

If you just think thru the directional concept that I can release enough air in 5 seconds that would take 3 minutes to replace ) you should probably put in your own numbers, some people have more serious compressors than others), this gives you the idea that storage is important, however one arrives at that solution.

Think of the extremist case where the new 80 gallon remote-storage tank is fed from a 140' x 1/4" ID line, and it takes 30 minutes to fill the tank....as long as the "burst" can be fed from remote-storage, and there's not another need for "burst" before the remote tank can recover, then there would be no functional problem with that setup (other than expensive frictional losses).

I'll even take the position that the best setup for the OP's original problem, given just a single air compressor, would be to separate the original compressor from the storage tank its presumably mounted-on, put the electric motor and pump head on a dedicated stand on one end of the building, and move the storage tank/air receiver to the far end of the building where air seems to be used the most ( if I understand the problem correctly).

 

[sberry]

No one is sure what stage the comp is. Still really don't even know the up, that sounds like wag at this point. It's about impossible to figure any of it out without the most rudimentary investigation. It's obviously easier to march off and start plumbing.

 

[Wrench97]

How old is the 3/4" pipe?
It almost sounds like you have a restriction in the line to me.
Mine runs 175psi/125psi and we run 1" guns 150' from the compressor on 3/4 pipe and 1/2" hose.

 

[sberry]

You missing the point of physics, his pipe is too small a diameter for the length based on his air demands.

When he installed a tank the pressures didn't change, but the volume of air is much closer now so it works for him, that is one workable solution, as was upping the size of the pipe.

FYI
it worked before he moved it... so PSI is fine.. and it's working now that he move a considerable amount of air storage closer.

I am not missing it. It was barely working before, he simply aggravated it. One of the earlier posts mention, they running 3/4 or inch guns at 150 ft on 3/4. I run 3/4 on long 1/2 but I got it set right. That's the physics being missed here, physic is we don't know what comp is there, might have fixed this by turn of a screw.

 

[sberry]

There is nothing fundamentally wrong with adding a second. It might take a little bit for some fundamental concepts of air transportation to kick in yet.

 

[39CAMC]

If you just think thru the directional concept that I can release enough air in 5 seconds that would take 3 minutes to replace ) you should probably put in your own numbers, some people have more serious compressors than others), this gives you the idea that storage is important, however one arrives at that solution.

Think of the extremist case where the new 80 gallon remote-storage tank is fed from a 140' x 1/4" ID line, and it takes 30 minutes to fill the tank....as long as the "burst" can be fed from remote-storage, and there's not another need for "burst" before the remote tank can recover, then there would be no functional problem with that setup (other than expensive frictional losses).

I'll even take the position that the best setup for the OP's original problem, given just a single air compressor, would be to separate the original compressor from the storage tank its presumably mounted-on, put the electric motor and pump head on a dedicated stand on one end of the building, and move the storage tank/air receiver to the far end of the building where air seems to be used the most ( if I understand the problem correctly).

Actually, the far back area is the most sensitive to PSI, but I typically don't use a lot of CFM back there. The high flow requirements would be from the metal fab shop who is between the compressor and my stuff in the back. We have a plasma table going there, and also lots of metal prep using die grinders, etc.

No one is sure what stage the comp is. Still really don't even know the up, that sounds like wag at this point. It's about impossible to figure any of it out without the most rudimentary investigation. It's obviously easier to march off and start plumbing.

The compressor is 2 stage. I apologize for not having the info up front. For various reasons, we are uncomfortable running it at full pressure capability, but if the 2nd tank thing doesn't work out, we will probably turn it up and see what happens. Or put the newer compressor that I am using as a storage tank in.

How old is the 3/4" pipe?
It almost sounds like you have a restriction in the line to me.
Mine runs 175psi/125psi and we run 1" guns 150' from the compressor on 3/4 pipe and 1/2" hose.

I think I covered this, but apologies if I did not. The iron pipe is 4 years old and the RapidAir on the long run was put in last winter.

I am not missing it. It was barely working before, he simply aggravated it. One of the earlier posts mention, they running 3/4 or inch guns at 150 ft on 3/4. I run 3/4 on long 1/2 but I got it set right. That's the physics being missed here, physic is we don't know what comp is there, might have fixed this by turn of a screw.

As I clarified above, the stuff at the end of the long run is just a tire machine and alignment rack with air jacks. Neither uses a lot of air, but both, especially the tire machine, are pressure sensitive.

The stuff using a lot of flow is in the middle, and much closer to the compressor and not a problem.

And like I said above, we are not comfortable just turning the compressor we have up to 175psi. We didn't get it new and has an unknown maint history, it is fairly old, it is mounted up in a mini mezzanine and fairly hard to get to, etc.

In the overall scheme of things, a new compressor is not a huge expense , BUT it has not been the most stable of years in business, so I am not rushing out to spend $2-4k on a replacement compressor until I have to. Hence where I ended up experimenting with stuff we had on hand.

There is nothing fundamentally wrong with adding a second. It might take a little bit for some fundamental concepts of air transportation to kick in yet.

I am not sure what you are getting at here and would like to learn. 2 medium use days in, the second tank has fixed the problem to the extent we need. I realize it is not perfect, we still have a pressure loss somewhere and even if the line sizes are correct, the location of the compressor versus the air usage is not optimal.

No argument or disrespect intended, I thank all for the info and help with getting my mind wrapped around the issue.

DaveW

 

[sberry]

What makes you "uncomfortable" about using the tool as it was so carefully designed to do? This is made for it, exactly for this. If guy is going to haul 200# why buy a 350 truck. I don't wanna rev the engine in to operating range so I will get another truck. Could using staying in second gear as another analogy. Maybe others can come up with better. Why they buy this in the first place, might as well got a 400$ pos.
It will store close to 2x the energy at full power.

 

[39CAMC]

What makes you "uncomfortable" about using the tool as it was so carefully designed to do? This is made for it, exactly for this. If guy is going to haul 200# why buy a 350 truck. I don't wanna rev the engine in to operating range so I will get another truck. Could using staying in second gear as another analogy. Maybe others can come up with better. Why they buy this in the first place, might as well got a 400$ pos.
It will store close to 2x the energy at full power.

How do you know it was made exactly for this?

We got it third hand. It was pulled from service by our powder coater because he went with a screw type and sat in the corner for 5 years before we got it. He used it for several years and was not clear on it's history before that. For what we paid, it was worth the risk.

All we know is that it is a brand name pump (i forget which brand, my partner did the details on this) but we can't determine its age and we have no idea if the pump matches the motor or anything else. We also have no idea the age or condition of the tank. All we can guess on all that stuff is "very old"

Given all that, we don't see the need to run it at redline since we don't even know what redline was supposed to be originally, and even more so since the second tank appears to have fixed the problem.

If I had come here and the general opinion was that the second tank would do no good, I would have probably tired turning the screw and see what happens, but since the problem seems fixed, we'll see how it goes.

When/if this compressor dies, we will replace with a new one of appropriate specs and brand, but there is no reason to drop $2-4K until that point comes, especially with the uncertainty of Covid.

DaveW

 

[imjustdave]

How do you know it was made exactly for this?

We got it third hand. It was pulled from service by our powder coater because he went with a screw type and sat in the corner for 5 years before we got it. He used it for several years and was not clear on it's history before that. For what we paid, it was worth the risk.

All we know is that it is a brand name pump (i forget which brand, my partner did the details on this) but we can't determine its age and we have no idea if the pump matches the motor or anything else. We also have no idea the age or condition of the tank. All we can guess on all that stuff is "very old"

Given all that, we don't see the need to run it at redline since we don't even know what redline was supposed to be originally, and even more so since the second tank appears to have fixed the problem.

If I had come here and the general opinion was that the second tank would do no good, I would have probably tired turning the screw and see what happens, but since the problem seems fixed, we'll see how it goes.

When/if this compressor dies, we will replace with a new one of appropriate specs and brand, but there is no reason to drop $2-4K until that point comes, especially with the uncertainty of Covid.

DaveW

Any chance you can give us a few photos of the tank, pump, control box, basically anything past just metal, any tags or plates. Usually on the tank will be a metal plate welded on the side. should have specs for capacity, PSI, birthday ETC.

Also do you have an idea of how many grinders, sanders, ETC your running here? How many people are in the shop running tools.

Basically we need real info of supply and demand, or at least a good baseline. your idea of an old basic compressor might be a gold mine that is running at half capacity that could run just fine at 100% Or maybe you have some POS that is runing at 130 % now. we are sort of guess at this point.

Initially I was thinking 1-2 people running a rack and tire machine but with a bunch of demand in the middle... and high demands air grinder, sanders you could easily be draining you line as if it was wide open. extra tank is providing air both directions, basically doubling its size.

In terms of maintenance, why not do an oil change? or at least see what the oil looks like.

 

[imjustdave]

I am not missing it. It was barely working before, he simply aggravated it. One of the earlier posts mention, they running 3/4 or inch guns at 150 ft on 3/4. I run 3/4 on long 1/2 but I got it set right. That's the physics being missed here, physic is we don't know what comp is there, might have fixed this by turn of a screw.

After I reread my post I wasn't trying to be snarky on my reply.

When it comes to running tools maintaining pressure and volume is key. Even at 150 psi I noticed a change going from 1/2 line to 3/4 at 100 feet on my impact gun. It worked on the 1/2 but ran way better on 3/4, and bolts prior that were not budging did after the change.

I think the OP biggest change or improvement with the extra tank is the extra storage allows air to come from 2 locations now. Front and back have local big storage short lines and in the middle he basically has 2 3/4 supplies. of air during high demands, and he has plenty of stored air when he is filling tires, and running the lift jacks at the rear. I bet the plasma cuts better and grinders are working better as well, and the off periods of time the system tops off again. Pretty easy to verify if they installed a valve at the far end.