You squeeze the trigger on your blow gun, you get only a short burst of air, and then the air flow dribbles down to almost nothing. What’s wrong with the compressor?
To understand that, we want to discuss the flow path of the compressed air from the tank.
The schematic below takes the convoluted (possibly) flow path of the compressed air on your air compressor, and turns it into a straight line for easier understanding.
In this compressed air flow graphic, the compressed air flows in a left-to-right direction. Air flows from the tank, through the regulator and to the discharge air coupler.
Air typically cannot flow past the discharge coupling until there is a connector inserted. Inserting the connector opens the check ball inside most “checked” air couplings and allows air to flow through it. That is why all the air in your compressor tank doesn’t flow out the coupling all by itself.
Let us assume that farther to the right, at the end of the connector and air hose you have a blow gun installed. You pull the trigger, and you get only a short burst of air. Here may be why.
Compressor Tank to Regulator
In the drawing there is nothing shown in the pipe between the compressor tank and the compressed air regulator most smaller air compressors come equipped with. The absence of another component in the line from the tank to the regulator is typical, and it is then reasonable to assume that if you have air in the tank, you will have compressed air flowing to the regulator.
Is there air in the compressor tank?
Of course, if there is no air in the tank, you will not get air flow to the regulator. Your compressor typically will come equipped with two air gauges. One will display the tank pressure, and the other, again typically installed on the regulator, will show the regulated pressure.
So, identify the tank gauge and read the pressure. If the tank is full, that gauge should read 100-150 PSI on a smaller air compressor.
Regulator gauge reading
Assuming that there is lots of air in the tank, the next thing you want to check is the reading on the regulator gauge.
The gauge in the photo is typical of gauges seen on smaller compressors. This one has a bottom mount. Yours may be a back mounted gauge, or it might be a panel mount gauge. If a panel mount, typically it will have a label identifying it as the regulator gauge.
Note the pressure on the gauge.
Whatever the reading is on your regulator gauge, that is the pressure that will flow downstream to your air tool. If this reading is low, lower even than the 50 PSI seen on the air gauge in the photo, that may be a reason why your air tool runs with only a short burst of air. If this setting is too low, then there will not be enough air to run the tool.
If your tank gauge indicates a pressure of 100 + PSI, turn your regulator knob to increase the setting on the gauge to, say, 90 PSI. Run the air tool. Did this solve the problem? If not, you have eliminated one potential roadblock of the compressed air flow from the tank to your air tool.
Is it the compressed air regulator causing only a short burst of air?
If you dialed the pressure setting on the regulator up and down by turning the adjusting knob, and the pressure reading on the regulator gauge changed up and down as you rotated the knob, then the odds of the problem being the regulator are lessened.
Since checking the regulator will involve a bit of plumbing changes on your air compressor, let’s leave the air regulator for a second, as long as the pressure display on the regulator gauge moves up and down with the turning of the adjusting knob. We’ll come back to this area if need be.
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Here is where we continue discussing resolving the air compressor problem of only a short burst of air coming out of the air hose.
I have a 1/2 hp , 58 psi central pneumatic airbrush compressor, I started my air to my gun begin to slowly dwindle away and I’d have to wait for about 30 seconds and then I’d get another short burst of air for about 2 seconds, and then it would fade out again.
I changed the regulator it did no good, I noticed the reed valve wasnt flat , so I flattened it ,no good….
But I also noticed when I took off the head that the sleeve for the connection rod was sitting there loose , I could just pick it up and slide it back on the rod…the compression ring seems fine took the rod out and slid sleeve on from the bottom it seemed tighter, but the compressor still only gives short burst of air then shuts off and wont kick back on until the tank is completely empty… any suggestions?
It’s a cheap compressor and I’ve already got a new one but I kind of like tinkering with them and just curious a to what’s wrong with this ,
The “short burst of air” for 30 seconds sure suggested a failing regulator. But later you say that i shuts off in between. That’s suggesting that the motor is overheating and going off on thermal overload, and that points either to a bum thermal overload switch on the motor, or perhaps a questionable capacitor.
If the motor is really hot when the compressor shuts off, that reinforces that it might be the capacitor. If the motor is hot, please see the page on testing the compressor motor capacitor linked from the troubleshooting page for tips on how to do that.
An update after checking would be appreciated by all visitors. Thanks.
Ok so the capacitor seems to be good , and your right it does get hot. It comes right on as soon as I hit the switch , the pressure goes up to 60, everything seems normal but as soon as it reaches 60 it shuts off and wont kick back on until the pressure is all the down to zero , I get just a short period of air , like a couple seconds, then I have to wait for the compressor empty out so it will come back on
What do you mean when you say the “capacitor seems to be good”, Mike? The symptoms point to a power supply issue. I suspect it’s the power supply through the switch to the capacitor, the capacitor itself, or the motor.
Thanks I’ll try that , I’ll let you know
so after reading your article and doing my own trouble shooting i think it is the discharge coupling. Here is why, if i push the the hose connector harder into the coupling, i hear air go past the coupling into the hose, i get a short shot of air, as in whats charged in the hose, and hten it dies off. I pushed the connector harder into the coupling again, and again, i hear air pass, and the hose fills up..
Based off of this, should i replace the coupling, and are the simple to replace??
Thanks for your article and diagram, it really helped.
Glad it helped. As noted in the couplers and connectors section, all are NOT interchangeable. It sounds to us as though you have a coupler to connector mis-match. Find a coupler and connector that works, and use that make and model on all your air connection needs and discard the ones that are mismatched. Replacing them is easy. Empty all air from the tank, remove the existing discharge coupler with a wrench, and replace it with a coupler for which you have the right connector. Or, find the right connector for that coupler, one that allows free air flow when it is inserted, and use that connector on all your air tools, air lines, etc.