Air compressor

[3eagles]

When I let my Air compressor catch up to 120lbs and restart a tool the line pressure seems very low for a few minutes. What causes this? I am using 1/2" black pipe with a max run of 25 feet. I have 5 vertical connections with quick disconnects on them. This allows me to move my tools around the shop without a lot of hose. I've even tried a air nozzle on this set up and the output is still low for a while. It's not like a clog, more like it just takes a while for pressure to come up in the pipe! Weird I think. Any help appreciated. Chuck in NH

[amerdunbar]

It sounds like there is a blockage someplace - rust perhaps in the black iron. Did you use pipe dope or teflon tape on the fittings? If even your closest connection drop is like that, I'd check it right at the compressor. Does it have a built in regulator - it may be sticking?

[3eagles]

I used Teflon tape on the threads and was careful not to get any overlap in the pipes. I have a pressure gauge at the compressor that reads 120 when it's full. But I hadn't thought about moving a tool to the first connection to see if there was a difference. Thats a good idea that will let me know where the problem is. I set up all my tool points on quick disconnects so I can move along the line until I find a drop.
I'll let you know what I find. Thanks, Chuck in NH

[amerdunbar]

Let me know what you find. I want to do the same thing when I build my shop - I'm getting sick of the spaghetti mess running all over my floor in my temp garage.

[FigureLLC]

if you look around on websites about compressed air system design, they typically recommend installing pressure gages at various places in the system, i.e. the drop legs, for diagnosing such problems. your problem sounds odd if your description is accurate. usually the air will start at full pressure and die down a bit as its flowing, due to restrictions (couplings, elbows, small pipe, hose) causing friction with the moving air.

[3eagles]

I moved the water seperator further down the line and made a more direct connection from the compressor to the system. Seems to work much better. When I can clear out the garage I'll re-plumb the setup using the drawing at:
http://www.oldmobility.com/images/acpipinglayout1.jpg
as a guide. The layout makes sense to me. Thanks for all the advice. Chuck in NH