Is our air compressor getting too hot at 181.8 F?

I tried to draw the needle at the correct psi.

It will be accurate to the downstream pressure at all times, not just while their compressor is off.

If the needle is vibrating while The compressor is on, The gauge is reading the upstream or reserve pressure.

Can you post photos of your setup? In particular, all gauges and the directions of arrows coming out of the regulator.

To be more specific: The input from the compressor must come in through the port opposite the arrow. The port with the arrow and the ones 90 degrees on either side of it are all regulated outputs.

Basically, you turn the knob. IIRC, there is a ring which needs to be pulled up for this to work. A bit counter-intuitively, you turn the knob to the right to increase the output pressure and to the left to decrease it.

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I will make another post tomorrow with pics of the setup we’re testing.

Back in the day we did some thermal testing with the Vlair 90C compressor with and without a fan cooling it. I highly recommend using a fan if you’re using the compressor for anything besides gear shifting or other light-use applications.

Testing data for reference

But it’s running so hot that the tubing is softening. Ignore the readout on the pic of thermometer–it’s evidently amateur-league garbage and outputs nothing but lies.

The compressor is seated in an open air environment and we’ve got a single pneumatic cylinder in the circuit. Judging from the advice in this thread we’ve either got some components attached incorrectly or major leaks that are causing the compressor to run overtime.

People are also very and truly insistent that the regulators be set to specific PSIs, but cannot or will not explain how to confirm which PSI they are set to or how to reset them in case they are not. So it goes.

Why can’t you plug the fan into the vrm?

I don’t think a fan is going to put a dent in the heat this compressor is outputting. The compressor never shuts off after the first cylinder deployment/actuation/shooting-out and it just gets hotter and hotter.

Please test to see whether the “never shuts off” behavior is true while the cylinder is extended, or after the cylinder is extended & retracted.

Please post photos & specifications of your setup. Tank sizes, cylinder sizes, solenoid part number, etc. Including how your regulator is set up, with “reserve pressure” and “working pressure” sides clear from the photos. Including how your solenoid is set up (part number, where it’s wired, what voltage, etc).

It’s risky, I wouldn’t do it.


A short circuit attached to the VRM will take out your radio, don’t attach anything that’s not the radio to the VRM, attach the radio to the VRM twice (once through barrel plug & once through Power-Over-Ethernet), protect both sets of wires like your match depends on it (because it does).

What exactly do the white needles on both gauges do when the robot is off? What numbers an/or can you see them falling? The white needle should rest immobile on the desired number (60 farther from the compressor and 120 closer). Loosening the nut and turning the knob should move the needle on each. See sneff’s image above.

Note the gauges should read the same when the robot is on and compressor automatically shuts off, and not above those numbers even when the compressor is on. (I just thought “turn it off” might cut to a less confusing baseline for now.)

ETA: This is a slightly different gauge (different unlocking mechanism), but does this help?

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I hope groaning and rolling my eyes is not how I came off as that’s far from what was actually going on. It is my intention, and the intention of almost all of the other great people on this forum, to help each other solve problems and learn.

This form is here for a few reasons, but the most important of which is, in my opinion, to help people like you. Hopefully we have been or will be able to do just that.

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It’s not that they aren’t explaining. It’s that you’re not understanding the explanations, which is at least somewhat understandable, particularly if you’re new to pneumatics. (I understood what they were trying to say, but I’ve been doing this for a while.)

Is our air compressor getting too hot at 181.8 F? answered the question with pictures. I’m going to try to walk through the answer without them, and I’ll reference the pictures as needed.

  1. Verify that you have 2x gauges in your system. One on the regulator or between it and the cylinder (downstream/low pressure gauge), and one somewhere between the compressor and the regulator (upstream/high pressure gauge). Fill your system. If they both read 60 PSI, the regulator is almost certainly the problem. [NOTE: If you don’t have two, you need to, because rules.]
  2. Verify that the regulator is pointing the correct way–see linked post. High pressure goes opposite the arrow.
  3. To set the regulator: Fill the system if you haven’t already. Pull UP on the black ribbed part–it’s a knob. Watch the downstream gauge. TURN the knob one way and see what the gauge does. Turn either the same way or the other way until the downstream gauge reads 60 PSI. Push DOWN on the knob to lock it.

Question: Is your tank upstream or downstream of the regulator? If it’s downstream, it’s not going to have a lot of air storage. Move it to the upstream side to double your storage capacity and halve your compressor usage. Or add a tank upstream to triple your storage capacity (approximately).

Question: Have you checked for teflon tape on your fittings on the cylinder and solenoid? (And that the fittings are tight?) If there isn’t teflon tape, or the fittings are loose, you found most of your problem.

Question the dumb: Describe the wiring of your pressure switch. There’s a slim but non-zero chance that there’s something off with that, particularly if your Pressure Relief Valve (the brass thing sticking UP from the compressor in the original post) is venting. I’d tell you how to check the PRV for proper calibration but that’s best done in person due to complexity–I think of us all, @GeeTwo is the closest.

I’m not trying to roll my eyes either, I’m trying to help you understand, and that may involve talking in what I’d call “highly simplified” language. Unfortunately, that’s what happens when you try to go from technicalese to less technicalese.

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Regulator set at 120 psi》Storage Tank for compressed air up to 120 psi》2nd regulator set at 60 psi.
Compressor will load until it reaches 120 psi. Then shut off or unload. When down stream line psi falls below 65 psi. Compressor will load ( create air pressure) until it reaches 120 psi and then unload/shut off. This off time gives the compressor time to cool down the oil and components from premature failure due to heat stress.
If both regulators are set to there correct settings and the compressor keeps running you either have a air leak down stream or one of your regulator pressure switches are failing.

That first one is a Pressure Release Valve. It’s designed for safe release of air over a certain pressure. A regulator won’t vent air if it’s set up properly–it’ll just not allow it to flow through if the pressure on the other side is at the specified pressure already.* A Pressure Release Valve is designed to release pressure if there’s too much. (And if it’s not set correctly–125 PSI–then you could have some interesting issues.)

*The classic regulator error is to install it backwards, or for a multi-port, 90 degrees to what it should be. In that case, it’ll vent, because it’s trying to regulate decrease a 60 PSI system to 120 PSI.

Oh I know! I was just starting to feel like I was asking the same question over and over and getting annoying!

Absolutely not. In part we are doing the divided by a common language thing (once you know the part names and the process there will be an ah hah moment and it will make sense), and in part I think you either have a defective part, a leak, or something configured very wrong. Any of these will cause your compressor to run continuously trying to build pressure.

What you should see is:

  • power up the system, gauges read 0 PSI, compressor comes on
  • pressure gauge up stream of the regulator (between it and the compressor) should start to rise
  • pressure should climb to whatever you have the pressure switch set to (typically 120 psi)
  • compressor will turn off, pressure should hold steady
  • pressure gauge on the regulator will read something. Adjust the regulator, via rotating the ribbed knob (usually have to pull the knob up, or push it in). Pressure should change as you rotate the knob. Set the pressure to whatever working pressure you want. Typically 60 PSI.
  • at that point you should have the high pressure gauge reading 120 PSI, and the low pressure gauge reading 60 (or whatever you chose).
  • system should stay like that, without the compressor running, until you use some air, by using your pneumatics
  • once the pressure drops, the compressor should run to bring the pressure back up

If that is not happening, something is wrong. First thing is to ensure that you have everything plumbed in the correct order (it should be very similar to figure 9-14). Then check for leaks. Also it would be very helpful to get a drawing or picture of your current configuration. Could you walk through the steps above, and describe what you are seeing pressure wise on the two gauges at each step.

Another potential issue is you have a small air storage system(one tank) and you are using a lot of air, (big cylinder, many cylinders, lots of actions) such that you are consuming air faster than you can supply it. If that is the case, you need to rethink your system. More storage tanks and precharging your air system before the match can help with a large cylinder, single action issue, but cannot solve a too much air demand situation. Can you explain what you are trying to accomplish with your air system?

One other suggestion. Simplify your system, and see if it works. I would suggest plugging it before the regulator and verifying that you get 120 PSI and the compressor turns off. That will verify the compressor, pressure relief valve, air storage, pressure switch, stored pressure gauge and the pressure vent valve/plug. Then just downstream of the regulator, and verify you get a stable working pressure. That will verify the regulator and its setting.

Once you have those, you know the control side of your system is working, and you can add in your mechanisms, one by one. Much easier to trouble shoot the system in sections.

A fan (or fans) will absolutely do a good job of keeping a compressor remarkably cooler. Natural convection around the compressor is probably in the 5-30 watt/(mK) range, where as forced convection from even a modest fan or two is probably in the 100-300 watt/(mK) range. It is reasonable to assume that a fan will dramatically increase heat extraction from the compressor.

In 2011 we were having a persistent issue with heat from the compressor softening the air tube connected to it. We put a small fan pointed at the compressor head and that completely solved the problem. Back around that time period we, and another few teams, collected and published some real numbers from our setups. I cannot for the life of me find it though…

This is what we’re doing this year: two fans zip-tied and soldered together…

Then strap these two directly onto the compressor fittings:

It may clear things up much more quickly if you reach out to other teams in your part of Louisiana and ask for someone with experience in pneumatics to visit your shop and show you how to make some of these settings. They might also see something that is connected incorrectly that you do not realize is incorrect.

This forum is great for getting many forms of help. Some things are easier done in person. That’s how I learned to work with pneumatics.

I did what you said, but started a fresh thread. Will you please take a look at it when you can?

here’s a link to the new thread! Compressor not kicking off; calibration difficulties