air regulator on compressor

savarin

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The air pressure regulators on my compressor appear to have a bit of a problem.
The main one reduces the tank pressure down to whatever its set for into a manifold where I can take of at that pressure.
The other end of the manifold has another regulator that I want to set for an even lower pressure for my powder coating gun.
The problem I have is that both regulators slowly bleed pressure into the line so that when the trigger is pulled there is a blast of over pressure before it settles down to the set pressure.
I've never really worried about this before as it didnt cause any problems but now I want to powdercoat its essential (in my opinion) that the air supply remains at a low pressure without climbing.
To have both regs do this makes me question whether this is normal.
If it isnt can anyone recommend a good make of regulator thats accurate and wont let the pressure climb when the trigger is closed on the gun.
 
Chances are the diafram has a small leek in it, I've rebuilt oxy/ace regulators before not air regulators
If you can get a rebuild kit for it would probably be cheapest .
 
I just find it suspicious that they both do it. The do cut off but at a higher pressure that they are set to deliver.
 
You may have some debris that is fouling the valves in the regulators. It is possible that there was some rust that got dislodged and traveled through the line to the regulators. I have a similar problem with the check valve sometimes sticking and draining the tank pressure through the pressure relief valve.

I would suggest that you try increasing the regulated pressure and opening the lines downstream from the regulators to try to blow any obstruction free. If that fails, you can take them apart for inspection and cleaning.
 
Thanks RJ I like that idea.
It feels like I'm never going to get this powdercoating system set up, one step forward and two steps back.
 
I've had this happened before and is down to dirt preventing the valve to close or wrong sizing on the pressure regulator, Cfm ratings too low.
If is a one time use you can try running a Y and connect a slow leak with a blowgun to help you get consistent pressure to finish the job.
 
It would probably be worthwhile to add a filter just before your last regulator (once you have it cleaned/repaired/replaced). FRL (filter-regulator-lubricator) units are often used on industrial machinery. If you could find one of them, you could run it dry for your powder coating gun.
 
I am adding an inline reg to the gun but as luck would have it I broke the adjuster off one of the other regs.
Grrrrrr
 
I just find it suspicious that they both do it. The do cut off but at a higher pressure that they are set to deliver.
Could the gauges be the culprit?
 
To get consistent pressure when spraying in this hot humid swamp, I would run two regulator/filters in series. with about 20' of hose between to act as a damper. The second regulator would be set to the desired pressure, the first regulator would be set to 25 psi over that.
 
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