Compressor Help

[geoff.clark]

I am trying to identify why the pressure release valve keeps dumping around 140 psi. I bought a new eaton compressor last year. I never had an opportunity to run it until this past month due to lack of money to finish wiring. So I ran into my first issue where the pressure switch had a broken on/off switch. I replaced this and now running into my current issue.

The prv dumps around 140, this is a 150 psi prv. I have spoken with eaton and they are telling me the check valve needs to be cleaned. I dont have a major issue with this other than it is brand new and why would it be clogged / dirty. I understood the check valve as a one way valve and would only dump back to the unloader valve when the pressure switch stops the motor.

Can anyone help explain why / how the check valve would cause the prv to dump before the max psi of the valve?

Thanks so much

[RanchFlyer]

I would be glad to help but need a little more info. You state the pressure relief or safety valve is 150psi but blowing off at 140psi . Where in the machine is the safety valve in question and why are you so close to the limit in the first place? My experience is to size a safety at 125% of the expected load but not to exceed any legal vessel or component pressure ratings.

[geoff.clark]

This is the compressor I purchased. http://www.eatoncompressor.com/catal...47/6474775.htm

It says it has a Max PSI of 145. The pressure switch was set to kick off at 145 PSI per factory. So my assumption was it was a 150 Pressure Release Valve. I agree it is very close to max if it is 150. But then next step up is 200 PRV to my understanding. So should I just dial this down to 130? I just want to make sure I do the right thing here and stay safe.

Thank you

[RanchFlyer]

I will start with the question from the first post. Not all safety valves are created equal. They all should have a rating stamped on them or a tag attached. A $2.00 valve is slammed together with a preset spring and probably has a +- %10. That being said I am not surprised to see a 150psi re-leaving at 140psi. A $35 valve in the same size will be assembled, tested, then shimmed to a +-%2. Now eaton compressor wanted to deliver on value accepts less quality on valves. That is not big news and certainly not a slap on eaton compressor, as it is accepted practice in the world in which we live. Second question where to go from here? Being as that is a single stage compressor I would back down my shut off pressure to 130PSI. More than that is asking alot from a single stage machine I don't care what brand it is. On a side note I like some of the features that eaton is taunting; slow speed, ring valves, magnetic starter, cast iron pump. A well bought compressor is a lifetime purchase for all but extreme cases.

[truckdude239]

my shop compressors are set to shut off at 175psi and the blow off vavles open at 200 psi

[geoff.clark]

Thank you for your responses. I will back this down to 130 and test. Thank you again.