I have a 3hp 200L compressor that runs at 10 bar (150psi). Basically one of the big ones machine mart sell.

I'm having trouble with the cut out pressure, it fills to 10 bar, cuts out but then doesnt come back in until its dropped to about 40psi.

I noticed this was a problem last week when I was spraying the chassis.

I would like to maintain the pressure maybe over about 100psi. Would that be right for a spray gun?

Is there a way to adjust the cut in pressure?

To help matters a little I'm just in the process of changing the pipe from the tank to the regulator from a 8mm flexi pipe to 15mm copper.

Thanks,
Steve

the switches are normally adjustable,
but be carefull, as its also easy to adjust where it switches off as well

Hi buddy

I'm sure I used to spray at about 45 - 50 psi mate, used to thin the paint enough to get it through at that pressure and everything was ok, took a bit of trial and error.

Cheers

R

Think if you use one of those top fed gravity types think the pressure is even less too.

Cheers

R

Yep, gravity feed, runs good at 55psi..

Only problem was the gun dropping down to 40psi before the comp cut back in.

Anyways, off to youtube and a couple twirls with the spanner now cuts out at 155psi and cuts back in at 110psi.

Sorted.

Thanks again,
Steve

My gravity gun runs at around 30psi and my compressor cuts back in when the tank is a 90psi. I can spray continuously while the pump refills the tank and cuts out again so no waiting time.

You should be able to adjust the cut in and cut off pressures.

Most air tool require around 100psi. Our compressor at work is set for 80-120psi and thats a good compromise between pressure drop and it running too often and constantly cutting in. I'd say adjust yours to similar; Check your air-tools and you'll probably find 150psi is too much.

For your spray gun you need a PRESSURE REGULATOR (and a water trap) in the line set at the required lower pressure. That will keep constant pressure. Just put a male and female air-line connector on each side and then plug it in between your compressor and air-line when using the spray gun.

[Edited on 19/8/13 by adithorp]

[Edited on 19/8/13 by adithorp]

Typically the pressure switches are a fixed differential - but have an adjustable upper limit both my 10 bar compressors have switches with a 2 bar differential switching off at 10 bar and back on below 8 bar 150 / 115 PSI respectively. The air pressure regulator for the tools is then set for what ever I am using.

Newer HVLP guns run at about 35-40 PSI - Tools like Die Grinders etc. 70-90PSI.

Sounds like your pressure switch is goosed or has gone out of cal due to vibration if its an adjustable differential type.

I have a water trap/filter/regulator for the spray gun and another with a lubricator for other things.

Just bought a new gun with a small regulator so was thinking of setting the first one @ 75psi and the one on the gun at 45psi.

I'll see how that works when I spray the bumpers and other little bits n bobs.

Don't use your oily air line for spraying unless the trap is at the gun end with a separate bit of line to the gun.