Compressed Air Guru

[Jacko]

On this forum we have a guru for most anything. I hope we have a Compressed Air Guru who can help with
an issue I have with my air compressor/system. When I use the nozzle initially there is a big blast of air that lasts maybe
a second or two followed by a steady rush of air at a significant reduction of force. My compressor kicks off at 125 PSI and
kicks on at about 75 PSI and it makes no difference if the pressure is high or low it acts the same. I have adjusted
the 'regulator'? up and down with no change. Any ideas? It just recently started this.


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[Kenny_Z]

Faulty or leaking regulator maybe? I had a regulator fail but all it did was stop regulating. Does it blast on every pull of the trigger?

[Bitsyncmaster]

Watch the pressure gauges when you use the blow gun.

[Jacko]

Yes, to explain more fully. The air pressure can be any where from 90 to 125 PSI and I get a large blast when
I pull the trigger
then it drops to 40 or 50 PSI ... not enough to run an air tool. I have turned the knob stop to stop with no change.
Maybe the regulator needs replacing? It just started this last week.

[dmc6960]

Yes, you most likely need to replace the regulator. Is that filter upstream or downstream of the regulator? If upstream perhaps it isn't working right, but I'll still bet its the regulator.

[DMCMW Dave]

Bad regulator or plugged filter. Eliminate them one at a time.

[Jacko]

The filter is down stream. The compressor is outside with the piping you see in a corner that disappears in the wall up
to the attic. There are four self-reeling drops at various places in the ceiling ... keeps the hoses off the floor and out of the way.
I'll buy a new regulator Monday ... Thanks Guys!

[DMCMW Dave]

In your picture there is a dryer (what I called the filter) is right next to the regulator. That could also be plugged.

[Jacko]

In your picture there is a dryer (what I called the filter) is right next to the regulator. That could also be plugged.

Yes Dave, the filter could be partially plugged. I bit the bullet and ordered from Northern Tool a 'piggyback' unit that has both regulator and filter built in.
Cost $129.00 with free shipping. I bet that solves the problem. You know, it's interesting to note how much we've come to rely on compressed air in the
shop. I have forgotten how to drive a nail with a hammer!

Again, thanks guys!

[Jonathan]

If you get a big shot of air when you initially use it after it has sat for a while, and then get a continuous supply of air at a lower pressure afterwards, one of those components inbetween the compressor and the nozzle trigger is problematic.

It sounds like it is letting some air by (hence the low force air and the 40 psi reading on your gauge) but not the full amount. When the nozzle trigger is closed, it gets the chance to build up, giving you the burst, but then once that volume is expelled, it settles back into the restricted flow/pressure.

If you are reading the pressure gauge at 40 psi, my guess would be the faulty component is upstream of the gauge. If the restriction, and thus pressure drop, was after the gauge, you would still see the pressure built up on the gauge. If there is a gauge directly on the compressor/receiver, it might show the normal/higher number as well.

The filter/dryer could be plugged, as others mentioned. Some of those can be designed to trap moisture and some oil as well. Instrument air can be referred to as "clean, dry air" and the clean and the dry part are often where the moisture is gone as is the oil. Maybe not so much in a home/shop system, but oil is important to get out of the air if you are feeding process control valves or certain instruments. Oil often gets in from the compressors themselves having issues, or needing maintenance.

If it is just a simple filter/dryer, sometimes there can be a little plunger type spigget on the bottom you can push up on or relieve and it will try to expel anything stuck in it. Like a blowdown valve kind of. If you feel like you are getting the full force of air out the bottom of that filter, then your problem has been narrowed down to between the downstream side of the filter and the upstream side of the gauge you are seeing 40 psi on.

And could easily be the regulator too, but harder to see. If it is one where you dial the top in or out, you're basically opening or closing a valve/restriction in a controlled way to let more or less air past it. Something could have gotten screwy in there or isn't seated or is jammed.

If you already bought a replacement combo unit, that likely might fix your problem right there. Let us know how it goes when it's back assembled.

[SS Spoiler]

What is that twisted looking stick behind the piping? Future walking stick?

[DMCMW Dave]

What is that twisted looking stick behind the piping? Future walking stick?

Over torqued torsion bar.

[Jacko]

What is that twisted looking stick behind the piping? Future walking stick?

That crooked stick has occupied that corner for years, something I drug home from some exploration. That would
make a walking stick now that you mention it. I've added a picture of one of the self-reeling drops in the shop.

21134 21135

[Jonathan]

That crooked stick has occupied that corner for years, something I drug home from some exploration. That would
make a walking stick now that you mention it. I've added a picture of one of the self-reeling drops in the shop.

21134 21135

Sweet DeLorean parts Hall of Fame you have there hanging on the wall!!!

I like that. If you're more into fixing cars than hunting deer, you could mount your "kills" like this. "So, this here one nearly got the best of me. I saw him coming from miles away. It took a lot of concentration and determination to take him down, but I wasn't going to let that sway bar get the best of me. Ahh, those were the days :)" lol

[Jacko]

Sweet DeLorean parts Hall of Fame you have there hanging on the wall!!!

I like that. If you're more into fixing cars than hunting deer, you could mount your "kills" like this. "So, this here one nearly got the best of me. I saw him coming from miles away. It took a lot of concentration and determination to take him down, but I wasn't going to let that sway bar get the best of me. Ahh, those were the days :)" lol

That's funny ... it seems everything on the wall has a story. The Delorean steering rack, sway bar, and steering column were replaced systematically in my search
for the fabled 'Voodoo noise'. The one I heard coming from the front of the car when going around a corner. I would drive the car and listen to the noise until I thought I had it figured out ... "why, that's the roll bar" Wrong! Then I'd convince myself it was something else. Remember this was before the internet and I could only call
Ed B for advice. Anyway, it turned out the main body bolts were loose. Tightened them up and the noise was gone. And it's a good thing I found it because
otherwise I would have had half of 4915 hanging on the wall! :mallet:

[OverlandMan]

I immediately thought of this:

http://beastandbean.files.wordpress.com/2007/11/1869443257_fcf1e513c8-1.jpg

Sorry for the OT post.

[Jacko]

I'm happy to report I solved the air compressor problem. I first replaced the drier/oiler assembly
with no luck. That particular drop has a self-reeling 35' hose in the attic and the fitting that connects the hose
to the reel was partially stopped up. I cleaned the fitting and now I have to hold onto something
to keep from being blown away. It's funny how something we use every day can gradually get
worse without our noticing it.

Merry Christmas everyone! :wave:

[rdarlington]

I'm happy to report I solved the air compressor problem. I first replaced the drier/oiler assembly
with no luck. That particular drop has a self-reeling 35' hose in the attic and the fitting that connects the hose
to the reel was partially stopped up. I cleaned the fitting and now I have to hold onto something
to keep from being blown away. It's funny how something we use every day can gradually get
worse without our noticing it.

Merry Christmas everyone! :wave:

Sorry I missed this thread. I have a lot of experience with compressed air (not necessarily a guru though) and would've suggested you eliminate the hose as a test. Hindsight is 20/20 and I've been there. I've also had problems with using small hoses such as 1/4" lines that restrict the air flow too much. I'm going to plumb in 3/4" copper in my shop with fittings at convenient places as well as valves for draining moisture out of the system at low points. Maybe even this winter.

-Bob