The main tank pressure will only go to 30psi?

by Bill H
(Waco, TX)

My main tank air pressure will only go to 30psi no matter how long the pump runs.

Everything sounds ok and it pumps from 0 to 30 normal enough.

I can't detect where the air is going if not in the tank.

I read Bill's 4 things to check(there are about four things that could be the cause. Bad power supply, intake valves, pressure valves, gasket failure or piston seals.)

The power supply is good, and I pulled the head and piston rings and seals looked good. I am not sure how to check the valves. I thought it might be a pressure regulator. Anyone have help?
Howdy Bill. A pleasure to see that someone actually reads some of my scribblings! :-)

When you say pressure regulator, I take that to mean your compressor pressure switch, as that is what controls the on/off of your compressor based on the tank pressure it sees.

If, at 30 PSI, the pressure switch is not tripping the compressor to off, and the motor is still running, then power is still flowing through the pressure switch, the pressure switch is working. It just isn't seeing the cut out pressure necessary to allow it to trip and turn the compressor off.

That it pumps to 30 PSI before not going any further strongly suggests to me that you have a gasket, likely between the low and high pressure flow paths inside the pump, that lets go at that pressure.

As to the valve plate, the reef valves need to be examined to see if they are in good shape. Another check is the intake port when the compressor is running. Is there good strong suction or is air huffing out of there while the compressor is running?



Comments for The main tank pressure will only go to 30psi?

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Oct 31, 2014
only pumps to 30 psi
by: MIKE H

check the check valve at tank where main line goes to tank from pump. if it does not hold air in tank it will only pump to 30 -60 psi.

Jan 22, 2012
Central Pneumatic Compressor
by: Bill H

I got mine back running by repairing a blown gasket with a gasket material bought at an automotive parts, along with some gasket sealer. I cut the shape to fit the piece without trying to cut out the inside portions. After drying, I cut the inside portions away with an exacto knife following the walls of the piece...a perfect fit. Make sure to get the curved reed piece spring design to force the reed against the 3 holes it covers. Couldn't have fixed it without you and your readers.

Dec 18, 2011
Main tank pressure only goes to 30psi
by: Bill H

After searching your site further, I found the section on why it won't build pressure. I have the same model Central Pneumatic 96447 as described with the exact same problem. ( Guess I will try one repair before dumping it. Great site and thanks for the great help. Prompt replies are really appreciated and a pleasant surprise when they come.


You are very welcome, sir.


Dec 18, 2011
Cutaway drawing
by: Bill H

Is there a place to see the cutaway drawing where the gasket might be? If it gets to involved or needs special tools, I might be better off getting it repaired by a pro. That will probably cost as much as the compressor though.


I don't know the model, so don't know if the manual is available anywhere on line. If you go to the Troubleshooting section on the site map, toggle the link to Reed Valve Failure for a schematic that will give you the idea about what we're discussing.

I expect shop rates on compressor repair would be in the $60-$80 / hr range, plus parts... and you have the price of a new compressor if it takes more than a couple of hours. In my opinion, if you need professional help in fixing it, the typical DIY home air compressor is designed to be used up and thrown away, based on it's up front cost.


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Will not pump up car and truck tires?

It runs good and builds up pressure to 100 psi but I cannot get the tires to accept the air from the line. I just do not under-stand it.
I hear the frustration in your posting with a fully charged air compressor but no air going into the tire. So sorry you are having the problem, but you are not alone.

There is a clear path for compressed air from the compressor tank to the tire. Each of the components in that compressed air flow path need to be checked to find which it is that is preventing air from getting into your tires.

If you visit the Troubleshooting page, click the link to No Air From Hose for help in diagnosing this problem and suggestions for finding out if it is the regulator, the discharge coupler or just what may be preventing air flow.

And, you need to make sure that your tire chuck works and the valve in the tire works too.



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Model # 92504 - size of pulley & shaft?

by Gil
(Florence, al)

I have a Model # 92504 central pneumatic air compressor that does not have the large belt wheel (pulley), belt to connect large belt wheel to motor pulley and the bolt to mount the large belt wheel onto the compressor pump shaft. Does anyone know what size of each of these i need and where I can purchase them?

Bill says...

I hope someone can advise, though, if you have not talked to HF, that's the place to start. Central Pneumatic air compressors are their house brand.



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Oct 24, 2015
Central Pneumatic model 92504
by: Rich Z

I have the same air compressor [Central Pneumatic model 92504]. It's been a great unit, a few weeks ago I came out to the garage and heard the motor running only to find the flywheel shattered. I did some searching and found a cast iron replacement sold by Redsheller's store. It was not real cheap $120 plus shipping. I put it on, fit perfect just had to tighten the belt a little more. The air compressor is back to work again.

His part number is 380540952237 and a link for it on ebay

Hopes this helps others with this problem.


Jun 03, 2013
Central Pneumatic model 92504
by: Chris

Anyone know where to get a replacement pulley for the compressor side? Not available from HF. I do know its a 10" dia, 1/2" wide belt with a tapered shaft. Apparently these things grenade on a regular basis. The rest of the compressor is perfectly fine. Thanks

Feb 22, 2013
Pulley Grenade no replacement
by: Andy

I too have that compressor
I have model Central Pneumatic compressor
Model is 29 Gal 115psi
Item # was 92504
4HP motor Dual piston pump.

My FLYWHEEL has broken into several pieces. Oh I called HF and they have no reference. So the journey begins to find a large flywheel.
Sorry you are having these problems, Andy. Good luck with your search. I hope someone can post some information about where to find one.


Mar 20, 2012
by: Anonymous

10" pully has a .95" Shaft

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model 94724 trips breaker & compressor won't start

by Don
(Oceanside, CA, USA)

When the switch is turned on, it pauses a moment, then trips the safety button. The compresson does not start.
Could be a bunch of things, Don.

Please see the page under Troubleshooting about compressors that don't start, do the checks referred to, then comment here with your findings.



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