# Significant pressure drop



## ksi (Aug 30, 2020)

Compressor is:
5HP
15 CFM
80 gallon tank.

I have 1/2" steel lines coming from the compressor location. There's approximately 15 feet, although with six 90 degree elbows, to the pressure regulator.
From there, I'm 20 feet or so of 1/2" steel line to a hose reel.

If I plug in say my spray gun right at the tank and pull the trigger, the pressure will start at 120 PSI, will drop to 100 PSI within a few seconds and then hold 100 PSI.

However, if I do the same test from the end of the hose reel, pressure starts at 120 PSI and will drop to approximately 55 PSI and then holds the 55.
Similar results when I put a gauge on an air nozzle or on a die grinder.

Any thoughts on if this is indicative of blockage in the lines, or am I undersized with the 1/2" lines, or bad regulator or ??


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## iowagold (Jan 22, 2020)

check for restriction on the hose reel for small dia.
I run 3/4 on the lines.
then to the 3/8 nipples and couplers for the small stuff
and have a port for 1/2" for the thunder gun impact.

check the pressure before the hose reel.


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## iowagold (Jan 22, 2020)

click here for the 3/4 inch rapid air system
that is a link to the system i like..
it works great!
yea i was not thrilled with the idea of plastic line..
it has an aluminum core in the line.
super easy to setup!!
it goes in fast!!


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## stevon (Mar 5, 2019)

KSI,

Even with a 1" ID steel pipe on my system, I did see a 20 to 40 lb drop in PSI depending on air tool CFM demand, and my runs were relatively short 10 foot then 90 degree then 15 foot, etc. 1/2" or even 3/4" through 90 degree turns is too small of a pipe in my opinion. there are other restrictions described here too e.g. 3/8 fittings, swivel coupler inside of the 3/8 hose in reel. Bigger pipe and/or a two stage compressor (higher starting PSI) would help

Stephen




ksi said:


> Compressor is:
> 5HP
> 15 CFM
> 80 gallon tank.
> ...


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## iowagold (Jan 22, 2020)

i do sweep turns on the special pex lines.
but there are T's on the drops.

oh yea ksi what is the cfm on the spray guns air?

and the da as well as any air files.

and then how many do you need to run at the same time?

if it is just a one person small shop the 3/4 will work just fine.

if it is a larger shop then yes the one inch main line runs with check valves are a good idea.


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## ksi (Aug 30, 2020)

Thanks for the feedback. I'm going to upgrade to 3/4" feed and see how much that impacts things. I like the looks of that Rapidair package. May go that route.


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## iowagold (Jan 22, 2020)

that rapid air system is a fast install!!
and so far it has lasted over 7 years in the clients shop.

it has orings on the fittings.
pretty cool.
use the blue monster pipe tape on the npt fittings for the best results!
let me now if you need links.
pm me.


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