Thread: When is my air compressor full?

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Great news guys, It works, It actually works. So yeh, I checked once again to see if the pressure switch would kick in, and it did, one thing I noticed was that the pressure relief valve leaked a bit until the pressure dropped to about 100-115 psi, should tightening it solve the problem or is this normal?

Thanks for all the help and information you've gave me
Phil

Phil, glad you got it figured out. As far as the leak goes, is it leaking at the thre ads where it screws in or is it leaking from the valve? Threads, take it out and either use thread tape or pipe dope on it. If valve is leaking, you might be able get it to seat fully by popping it of a few times, or buy new one. If you get a new one make sure it has the same setting as original. That or just live with it. Good luck with your projects.

Bill

What's happening is, the relief valve is popping up at about 115 psi, so the pressure relief switch doesn't have enough pressure to turn the machine off. So the machine would be running all night long(non-stop), would it be safe to change the relief valve to one rated at 10bar ?, just to assure it didn't pop open to early again.
Thanks
Phil

10 bar is 150 PSI. Probably ok, but I would contact the mfgr before making that move. The unit should work as designed. They need to fix it.

[QUOTE=phil121;1004827]What's happening is, the relief valve is popping up at about 115 psi, so the pressure relief switch doesn't have enough pressure to turn the machine off. So the machine would be running all night long(non-stop), would it be safe to change the relief valve to one rated at 10bar ?, just to assure it didn't pop open to early again.
Thanks
Phil [/QUOTE

The "relief valve" is an over presure valve. That means that when the pressure exceeds a certian PSI it will open . It will close when the lower pressure is met. The pressure "switch" is a device that will turn the compressor on and off at certian pressures. An example is .when the pressure in the compressor reaches 80 psi it will turn on until it builds 110 psi then it will turn off.Hope this helps...............

I understand that the relief 'valve' should open after exceeding 120 psi, but that's not what is happening, the relief valve is opening before the 'switch' can turn on, so the machine runs continuously, and the pressure 'switch' doesn't come in to play at all. If I buy a higher quality relief 'valve' rated at 120psi, do you think it will solve the problem, instead of buying one rated at 150psi.
Thanks
Phil

Usually the working pressure for an air compressor is right around 100psi. Some are higher ,but most air tools that I have been using use between 90 - 110 psi. The relief valve could be set @ 120psi. If it is going off before this pressure the valve could be faulty. If the pressure switch is set for 100 psi and the relief valve goes off at say 90 psi, the compressor will keep running because it is trying to get to 100 psi and it can't because the relief valve is bleeding all the air off. I would check to see what pressure the relief valve opens, then where the pressure switch is set. When it starts,lowest pressure it goes to before starting, and where it stops, highest pressure it goes to before stopping. If the highest pressure is above the relief valve setting either the switch is set incorrectly or the relief valve is set incorrectly or faulty. Hope this helps and doesn't confuse you !!

I would contact the manufacturer first and find what it is supposed to go off at. Chances are it is close to 150. Most pressure switches are set around 125 is what I have found. Call the company and they might just replace it for free. Most tanks have a safety factor on them so they will withstand more pressure without problem.
hope you get it workrd out

Phil? is that pressure relief valve (Yellow) brass or is it plastic or mostly plastic? If it's plastic, i would replace it and get a sturdy Brass one to match......not that they should ever be made of plastic in the first place. Also, i agree with scarybill and test pop the PRV a few times. If that doesn't solve the problem then maybe you have a faulty PRV. Find out what the rated tank max pressure is and go out and buy a matching relief valve at that rating. I had to rebuild my second compressor from the ground up and replace the pressure switch, the PRV the regulator and the often overlooked, one way check valve. Once this was all done, i had a compressor that runs like a tank like the day it was made. At the end of the day, if this compressor is brand new and still has a warranty or can be exchanged at the store, do so ASAP. Also, keep in mind that the smaller 2-3 gallon compressors are for light-duty and will recycle frequently depending on use. They are ok for props and tools but they run almost all the time under a fairly light load so keep this in mind also.........