Bostitch is a popular DIY air compressor. This page has to do with reasons why a Bostitch compressor will not build any pressure. Comments and responses are below.
At the end of this page is a form where you can add a question if you would like.
My Bostitch air compressor will not build any pressure or very little?
by Ben Jones
(Morrisdale, Pa)
Oil free compressor does not build any pressure or very little?My bostitch pancake air compressor started by not shutting off when it hit the designated air pressure (continuously ran unless you manually shut off), but now it turns on and sounds weird and does not build any pressure or very little. What would you say is wrong?
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Ben, first off, that the compressor didn’t shut off at normal cut out pressure and you had to shut it off manually suggests the pressure switch has failed.
The weird sound you are hearing might be intake valves, pressure valves, blown gasket, motor failing, pump mechanical issue… it is pretty hard to tell from here.
When you say “but now it turns on and sounds weird ” do you mean that it is cutting in at the normal pressure setting, the compressor is running at the point, but no air pressure build up in the tank at all?
Can you please post a comment with more details?
Bostitch 6 gal oil-less air compressor won’t fill to full pressure
by Jeff
(Conway, sc)
My Bostitch 6gal oilless air compressor will run fine to around 50 or 60 psi, and then continue to run without gaining more than a couple psi.
No audible air leaking, and the tank continues to run just as before.
After a couple of minutes, I turn it off, drain it, then repeat and get the same result.
60 psi is about the max I have gotten. Any thoughts would be greatly appreciated as this compressor is very pricey and too expensive to replace. I’ve also taken the piston head apart and all the air valves are fine.
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Jeff, good that you checked the valves. Glad also that they are fine. There are other issues relating to air compressors that run and don’t build pressure.
Shut it down, empty the tank, remove, clean, and replace the tank check valve. Any change?
Assuming that the power supply hasn’t changed, you may be experiencing a pressure related gasket failure, or you might still be having a valve fail under load.
See the site map page, under the Troubleshooting category, for links to more info on why an air compressor will run and not build pressure.
Bostitch model# CAP60P – Won’t build pressure?
by Lane
(Alabama)
Bostitch model# CAP60P – OF
Unit won’t build pressure.
Main supply line to the tank at the non return valve gets real hot.
The compressor also has a higher pitch sound. The non return valve seems to be working. I’m wondering if it’s the valve plate assembly at the head?
Lane
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Lane, if you have air huffing out of the intake port on the pump head, then, for sure, you have a valve leak. Air is bleeding out fast enough that the compressor tank pressure can’t build past a certain point.
The pressure valve failing could be the cause, as well.
All compressor air lines from the pump head to the tank get too hot to touch. That’s why they are made of metal, so that symptom may not provide any clue.
Don’t know about the sound change, though that might be because of the valve issues, or an internal gasket leak at a certain pressure, or it could be that the compressor is running too long and overheating… it’s supposed to shut off fairly quickly after the pressure switch turns it on.
To correct these you will need to tear down the pump. You might as well have a valve kit and gasket kit on hand when you do. If the valves are at fault, you will have the valve kit ready. The process of tear down will likely destroy any gaskets, so not only will you not be able to tell if they were at fault, but you will need to replace them anyway, I suspect.
I have a bostitch 4 gallon compressor and it is not building pressure: Removed the cover and it builds some pressure then starts blowing air out where the fan is: Any idea. This is an older model and I only have part of the model no. Pancake 4Gals ol195 CETL K———-., Lot 006215, Code 8213340BWA019.
Thanks
David Jones
You, Dave, are in luck. OL195 is actually the pump (as opposed to the unit) ID. Look it up. Your piston ring is probably torn. You probably can see it from underneath the pump. You can get it and the cylinder for under $30. If you’re super careful and the cylinder is smooth, you may be able to get it in without removing the head, but it’s easier if you do remove the head. And you have to if the cylinder is scored, so you may need to get the gaskets, too. Note that the ring is installed with the… Read more »
my compresser is is blowing out very small amounts of air
Howdy, and perhaps you could let us know where on your compressor it’s blowing out small amounts of air, and, what the model number is?
I took the cover off of my compressor and when I turn it on the fan is running backwards as to the arrow on the fan. Any ideas???
Some fans cool by blowing air over the motor, some by pulling air across it. Have you had issues with the motor overheating?
What Bill said, and if you have the model number, you can probably find the fan part and see which way it blows and if you have the correct fan. Also, you possibly have a bi-directional motor, wired wrong, although that’s not likely.
Did u resolve the issue. I’m experiencing the same backwards fan.
Thx
Question:
Why are you and Clay concerned about the fan?
That is to say – What is the problem that lead you to notice the fan direction?
You have some other symptom – what?
We don’t know the model of your machine, but even if it is running “backward” that is not a problem in and of itself.
Please tell us so we can help you.
Can I restate the issue. I have replaced the mechanicals, piston, all new valve assemble et ct but did not touch the motor. when I started it the electric motor is running backwards.
How do I know?
The fan housing has a directional arrow and the intake is blowing all the air out and not sucking any in.
OK, there’s a data point.
We STILL do not know what machine you are talking about, though.
Maybe the arrow is wrong, maybe the fan is wrong, or maybe the motor is turning backward from design.
Still, depending on the design, it may or may not matter.
And we have no idea of the design for the reason stated.
We’d really like to help, but:
No model, no picture, no idea.
Bostitch model OL195. Air is blowing out the intake hole instead of sucking the air in to compress the tank. I could blow leaves with the amount of air coming from the intake, so of course the the tank stays at zero. The fan is not functional the way it is turning, it is only functional in the direction the directional arrow points. it is a squirl cage fan so it is obvious it is going in the wrong direction. It worked before the head replacement just would not get to 120 psi due to a bad valve. after the… Read more »
This is not related to the direction of the motor. The valves operate according to which way the PISTON is going. Your valve plate is installed incorrectly. Depending on which revision you have, probably rotating it 180 degrees will make it right. Or inverting it. When the piston is going up, the intake valve should be pushed closed, forcing the air out the exhaust valve into the tank. Conversely, when the piston is going down, the intake valve is pushed open, and the tank side valve is pushed closed. Once you have it apart, you should be… Read more »
Thanks that makes perfect sense I just did not have the confidence to push that thought forward due to the instructions said just clip the zip ties that hold the head plates together and install keeping all the orientation the same. I will give it a try. Thanks again. Rob
Thanks Doug, rotating the valve plate 180 degrees fixed the problem. Pumps up nicely. Now the connecting rod backed off the crankshaft bearing about an 1/8″ and cut through the squirel cage fan…. Do you put any adhesive on the bearing surface to hold the connecting rod from backing off?
Don’t rightly know. How ’bout some pix and maybe we can figure it out..It was working OK before?
Thanks for the reply. Yes the compressor worked ok until the belt broke, then is was a chain reaction. would not pump up with the new belt, so I bought a piston kit. When I installed the new piston I noticed a valve was broke, so I ordered the valve kit, which as you know was delivered 180 degrees out…. now it pumped up fine but after getting to 120 psi (one cycle) the conecting rod backed off the bearing at the crank an 1/8″ and cut the plastic squirl cage fan in two.. So I scuffed the bearing and… Read more »
LOL. You already did what I’d do.
If you do shoot it, can you make it a high-speed video (as in slow-mo)?
I hope it doesn’t come to that, though.
LOL. I will see what I can do. Thanks
Is it best for me to maintain full pressure or drain it and release pressure when not in use!
It depends!
How long would it typically be between uses?
If more than a day, drain it.