Air Compressor Troubleshooting

[snpower]

I've got a Central Pneumatic 2 hp 8 gal unit that my Dad bought me for a birthday gift. It's supposed to do 5 cfm @ 90 psi and 6 @ 40 psi.

I've tried three impact wrenches and each one won't turn a nut at all... in fact - I can hold the driver in my hand, squeeze the trigger, and keep the gun from spinning the impact driver.

I've tried two different air hoses. Each one is 3/8". The unit is oiled up and other than that I don't know anything about troubleshooting these. It does tires and other non-air tool applications just fine. If it weren't from my Dad and two years old I'd probably give up but hoping someone has an idea.

 

[Bird]

First, you could hold a socket on almost any impact wrench and it won't spin because your hand is not a solid rigid hold. Your hand will allow the socket to rock back and forth really fast.

Second, I've "tested" lots of impact wrenches just to see if they ran and sounded right with a 1/4" hose, but to use one on nuts and bolts, you won't have much power with a 1/4" hose; you need 3/8".

Third, what's the torque rating of the impacts that you tried? You can buy 1/2" pneumatic impact wrenches rated at 210 ft. lbs. up to more than 600 ft. lbs.

Fourth, doesn't that compressor have a pressure regulator, in addition to the gauge? If so, are you sure the regulator is opened to allow 90 psi or more through the hose.

Don't know whether this helps or not, but maybe it'll give you a place to start, because that compressor should run a half inch impact.

 

[snpower]

First, you could hold a socket on almost any impact wrench and it won't spin because your hand is not a solid rigid hold. Your hand will allow the socket to rock back and forth really fast.

Second, I've "tested" lots of impact wrenches just to see if they ran and sounded right with a 1/4" hose, but to use one on nuts and bolts, you won't have much power with a 1/4" hose; you need 3/8".

Third, what's the torque rating of the impacts that you tried? You can buy 1/2" pneumatic impact wrenches rated at 210 ft. lbs. up to more than 600 ft. lbs.

Fourth, doesn't that compressor have a pressure regulator, in addition to the gauge? If so, are you sure the regulator is opened to allow 90 psi or more through the hose.

Don't know whether this helps or not, but maybe it'll give you a place to start, because that compressor should run a half inch impact.

1. Understood.
2. The hose is 3/8. I just checked. Not sure why I thought otherwise.
3. The wrench is a Craftsman rated @ 240 lbs.
4. The regulator is set to approx. 100 PSI.

 

[Bird]

1. Understood.
2. The hose is 3/8. I just checked. Not sure why I thought otherwise.
3. The wrench is a Craftsman rated @ 240 lbs.
4. The regulator is set to approx. 100 PSI.

I'm not sure what nuts or bolts you're trying to turn, but 240 lbs. is a pretty weak impact. I used to have a Central Pneumatic (Harbor Freight) of that caliber. It was handy at times, but I found some lug nuts and lawnmower blade nuts that it just would not loosen. I finally got rid of it have an Ingersoll-Rand IR231 rated at 425 lbs.

Otherwise, if that regulator is really letting 100 psi through, I don't know what else it could be.

 

[snpower]

The regulator certainly makes sense. I tried my neighbor's 400 PSI wrench with the same results so I am fairly certain it's my compressor.

 

[Soundguy]

you can't use those coily lines.. has to be 'real' 3/8 ID hose or better.

you using that?

what's the pressure gauge say?

i've got a 12yr old pancake comp from HF.. have rebuilt the head with new gaskets and cleaned the reed valves. works good now that i put cardboard gaskets in , and not the gummy plastic stuff they had in it.

soundguy

soundguy

 

[snpower]

I'm using a good line from Kobalt (Lowe's) on a retractable reel. Pressure gauge is reading 100 PSI.

 

[Mace Canute]

A half inch drive air impact wrench need a certain volume of air to work properly, roughly 4 to 5 CFM (but that's just a ballpark estimate, it varies between makes of course). Cheap air pressure regulators limit the air pressure as they are supposed to but they also really throttle the air flow. It's highly likely the regulator is the bottle neck and isn't allowing enough flow to allow the impact wrench to work properly. Try it on tank pressure straight from the compressor. Don't worry about the "90 psi maximum" that you will probably see on the air tool, it ain't going to fail catastrophically from trying it, and several people have said they use their airtools at tank pressure with no problems ever...and these are people who use them on a daily basis.

BTW, here's a site that gives ballpark figures for air tool air consumption.

Air Tools and Air Consumption

 

[Soundguy]

i agree.. orifice regs kill flow.. not to mention some of the cheaper reel style hse setups have small ID's where the moving link is.. really limits air flow.

soundguy

 

[snpower]

A half inch drive air impact wrench need a certain volume of air to work properly, roughly 4 to 5 CFM (but that's just a ballpark estimate, it varies between makes of course). Cheap air pressure regulators limit the air pressure as they are supposed to but they also really throttle the air flow. It's highly likely the regulator is the bottle neck and isn't allowing enough flow to allow the impact wrench to work properly. Try it on tank pressure straight from the compressor. Don't worry about the "90 psi maximum" that you will probably see on the air tool, it ain't going to fail catastrophically from trying it, and several people have said they use their airtools at tank pressure with no problems ever...and these are people who use them on a daily basis.

BTW, here's a site that gives ballpark figures for air tool air consumption.

Air Tools and Air Consumption

I tried the wrench w/o the regulator and bingo it worked like a charm! Rather than order another one from Harbor Freight, might there be another regulator I could get that would work 'better'?

 

[Bird]

I tried the wrench w/o the regulator and bingo it worked like a charm! Rather than order another one from Harbor Freight, might there be another regulator I could get that would work 'better'?

Personally, I'd probably be looking at Northern Tool if I were looking for a regulator because they're close to me. I'm sure other places are just as good. Even Sears has them. Just what do you use that compressor for, besides the impact wrench. You know you don't really need a regulator for the impact. Impact wrenches, and most other air tools, are rated at 90 psi. More air pressure just gives you more power. A lot of mechanics are working with 175 psi. Of course, too much of that, too long, may cause something to break. When I was repairing air tools, I figured (1) too high air pressure, (2) inadequate lubrication, and (3) moisture & dirt in through the air inlet are what keeps air tool repairmen in business. But mechanics who use their tools every day may figure a repair bill occasionally is worth it to get their jobs done quicker. My current compressor works from 125 to 150 psi, I don't use my impact wrench a great deal, but I'd never bother to adjust the regulator for it.

 

[snpower]

Might run a nailer at some point but the day in day out use is to inflate tires and use air pressure to clean.

 

[Bird]

Might run a nailer at some point but the day in day out use is to inflate tires and use air pressure to clean.

I turn my regulator down when I use the paint spray gun; but nothing else that I can think of.

 

[kenmac]

might there be another regulator I could get that would work 'better'?

I bought my regulator from Lowes. Works good on my large compressor

 

[tallyho8]

I put a Tee on my Harbor Freight compressor with one side going to the regulator and the other connection straight from the compressor.

I rarely use the regulator side.

 

[Soundguy]

on my comp.. a 30g upright, it will pump up to 120 psi.. when i paint I turn down to match gun.. anything else.. I open it up full.

I have a 3/4 impact gun I run on 1/2" ID line off a t at the comp body to get more flow. it's paperwork also specified 90psi and some scfm.. but it runs great as do my 3/8 butterfly gun, and 1/2" gun and the air chissle /hammer.

soundguy

 

[kenmac]

I have to use the reg. My 1/2'' drive impact ( 600 + ft.tq.)will snap bolts if I'm not careful

 

[Soundguy]

I have to use the reg. My 1/2'' drive impact ( 600 + ft.tq.)will snap bolts if I'm not careful

my 3/4 is 2x that can twist off 1.25" headed bolts if not watching it..... however has a dial on it I can lower it's output right on the gun.. way easier to use the guns dial that dink with the reg on the compressor continously.

soundguy

 

[RobertN]

The local NAPA's carry that kind of stuff.

I tried the wrench w/o the regulator and bingo it worked like a charm! Rather than order another one from Harbor Freight, might there be another regulator I could get that would work 'better'?

 

[Larry Caldwell]

That 90 PSI and scfm rating on the tool is minimum air needed to run the tool, not maximum.

BTW, I have air tools that take more air than my 2 hp, 20 gallon compressor will provide, so I tapped out of the tank pressure to a recycled 40 gallon tank. It gives a much larger air reservoir, and gives the compressor time to get ahead of demand.