Hook up two compressors

There are sometimes good reasons for connecting two air compressors. A single air compressor may not offer enough flow to supply a higher demand air tool.
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Another, single air compressor, can have the same problem with that same air tool. But if you connect two air compressors into one line to the air tool, you may have enough air flow from the two air compressors to use that higher demand air tool. A quick review of how compressors work also covered in detail on a page on this site is that they have an air tank into which air is pumped. As you use air, the tank air pressure drops.

When the tank pressure drops to the pressure switch cut in level, the pump will start, and add more air to the tank until the tank reaches the cut out pressure setting, and the pump stops. However, if your air tool has a greater demand for compressed air than the compressor can deliver you will use air in the tool at a greater rate than the compressor can supply it, and even though the compressor is running, since it cannot keep up with the demand of the air tool, the tank pressure will keep dropping until there is not enough compressed air to run the air tool.

To use a higher demand air tool you will need a bigger compressor. Or, connecting two air compressors to the same air line to the tool, if you have a couple of small air compressors around, might work. If you have two air compressors, select which will be the primary air compressor and plumb a tee into the discharge coupler on that one. One leg of that tee is the supply from the primary air compressor, one leg of this tee is the supply from the secondary air compressor, and the last leg is where you install the air line to your air tools.

If we assume that both air compressor tanks are full of compressed air, when you start using your air tool, compressed air will be drawn from both tanks… at least, in theory. The reality is, compressed air always flows through the easiest path from high pressure to low. As air is drawn from the two compressor tanks to the air tool, compressed air from one tank will flow into the other tank and vice-versa, rather than all of it flowing down the air line to the tool.

connect two air compressors together ??

By installing a check valve in the line between the secondary air compressor and the tee of the primary compressor, this will prevent air from the main tank from flowing back into the secondary, improving the efficiency of the air flow. Once the pressure in the hose to the air tool drops due to air use, air will be drawn from the secondary tank. However, once again, air from the secondary tank may flow back into the tank of the primary air compressor rather than down the line to the air tool.

Another non-passing valve before the tee in the discharge coupler of the primary compressor, allowing air out of the tank, but not back into it from the other compressor. In order to achieve the desired pressure and volume for our pneumatic equipment, I need to inter-connect 2 compressors.

I need advice on how to go about doing it and need a couple of questions answered: Both good questions, and both covered extensively on the pages of this site already. Answer to question 1 - no. Answer to 2 - no. What you will do is increase the available compressed air flow at the pressure the system needs. Both compressors will plumb to the same air main to your plant.

Connecting Two Air Compressors

Both air compressors will have a one-way or check valve in their lines before the two lines connect to the single main. In order for one compressor not to be the one that's always on first, undergoing greater wear, periodically change the pressure switch settings so that the alternate compressor comes on first. Click here to post comments. I have 2 industrial air compressors. Both are v 3 phase with one being a 7 hp, the other a 5 hp. I am wanting one compressor to be the primary while the other acts as the secondary to kick during high peaks when compressor 1 can not keep up with peak demand times.

Connecting Two Compressors Together

I know there are a couple of different ways these can be plumbed together but, am not certain of the best or most recommended way to pipe these up. Suggestions and experience would be greatly appreciated. I get this type of question about putting two compressors together to increase flow and or have a backup for greater demand, quite frequently.

The frequency of the back-up compressor switching on will be predicated on the pressure switch settings of that compressor.

Connecting 2 compressors to get combined pressure and volume.

If you have the cut in pressure just below the cut-in pressure of the primary compressor, then the secondary will only come on when the pressure level in the primary tank falls below the normal cut in, suggesting that even though the primary compressor is running, it cannot supply enough air. At which point the secondary compressor would start too, even though the primary would be running as well. Both compressors can be plumbed to the same main. Assuming that both lines go to a common tee, and the out port from the tee goes to the air mains, ensure that you have a check valve in the line from each compressor to the tee so that air from one compressor doesn't back flow and out the unloader valve on the secondary.

Any further questions, please add them as a comment here so I can follow the thread. First, yes I am a d-i-y'er and new to the understanding of compressed air. You'll be missing some control and logic schemes, but the basics will work. In order to really benefit you will have to size all of your orifice restrictions for flow. The final unloader valves, or diaphragms, will work as crude check valves. If your regulators are downstream sensing the system will equalize itself.

Vacuum pumps work the same way. I have two 70 scfm, at 28"hg, units hooked up in parallel when they are used. As I said, it's kinda crude, but it will work. Join Date Nov Location N.

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Yep - you'll be fine. As Mike pointed out, compressors are ganged all the time.


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Just make sure you run each compressor off a seperate electrical circuit. My Coleman draws a full 15 amps and my Ingersoll Rand "hot dog" similar to your Emglo draws My sub panel in the garage is only 30 amps.


  • Connecting Two Air Compressors?
  • Connecting Two Compressors Together.
  • Ganging two small air compressors together.
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  • Ganging two small air compressors together.
  • I have to run one off the sub panel and the other off the house panel, otherwise I run into starving one or the other for current. Oh yeah, make sure the aux tank is rated for the same pressure as the compressors. My granddad always said,: As one door closes, another opens". Wonderful man, terrible cabinet maker Your proposed setup will work just fine. I actually read an article about this very thing minus the extra tank quite a few years ago in either Journal of Light Construction or Fine Homebuilding.

    I remember from the article that the contractor cobbled together an air fitting that he and his crew affectionately named, "The Double Dongle"--basically a T with two male quick-connect fittings and a female quick-connect, IIRC. Keep in mind, however, that you will still have the duty rating of the two compressors to monitor. So, 30 minutes of every hour it can run. I've used that to my advantage. If I can spray a coat of finish on something like a trim package in 30 minutes, with the compressor barely keeping up, then I can let it sit and cool for 30 minutes or more and not exceed the duty rating.

    I also have an extra tank, which was very useful when my father and I were roofing my house, running two roofing nailers. When we were both going gangbusters, the compressor would occasionally get a little behind, leaving nails proud. With the tank hooked up, we were good to go because it would help get us through periods when we were both nailing, then recover while we grabbed more shingles or moved or whatever because it meant more air available at the regulated pressure.

    Jason "Don't get stuck on stupid. Thanks all- this is great to hear. I can't believe I never thought of this before, I've had this equipment for many many years and always wished I had a bigger more robust compressor. As I said, I'm trying to make do lately with what I have.

    I've even got all the hoses and fittings I'll need.