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'?