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by Janet
(Penzance, Cornwall, UK)

I’ve got a small Jun-Air compressor that has always worked brilliantly and I use it with a stapler. It now doesn’t cut out but keeps filling with air then blows. You can also hear a small, hissing leak as it fills.

Thanks.
Jan
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Jan, two issues, I think.

First off, when you say it blows, I suspect you mean that the PRV lets go? That’s what is supposed to happen if the compressor doesn’t stop at the normal cut out and pressure continues to build.

So… stop using your air compressor until you replace the pressure switch. That’s what is supposed to turn your air compressor off and on at the right pressure, and if your compressor is not shutting off at cut out, it’s almost certain that the pressure switch has failed.

Next, the hissing noise, it would be good to know where the air is leaking. If it is bleeding out the unloader valve, then that points to a leaking tank check valve.

Have a check and please let us know what you found, and also upload a photo of your compressor so we can see what model it is.

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