Compressor Will Not Build Pressure



Why is it a compressor will not build pressure? The motor runs, the pump sounds like it's running, but the air pressure in the tank either doesn't rise at all, or rises to a point and then stops rising, even though the compressor continues to run.

A compressor is a pump. That pump pulls in free air from the atmosphere and is supposed to drive it into the tank, and that increases pressure in the compressor tank.

Different styles of air compressors, reciprocating versus rotary screw form example, accomplish this with different methods, yet they pretty much all do the same thing, suck in air and drive it into a tank.

What is there to check on an air compressor when
        the compressor will not build pressure?

The air compressor reed or flapper valves (also known as the intake and pressure valves, or suction & discharge valves) are a common cause of why an air compressor will not build pressure. The image below shows the pump of a small air compressor, and the valves on this model.

Compressor valve plate

This page gives you more information about the air compressor reed / flapper / intake / discharge / suction / discharge valves.

Want to check a few things more about why your air compressor will not build pressure? Here is a page that summarizes some more things to check.

If that still does not help, use the form to ask a question about what to do when your compressor will not build pressure? Please provide as much information about what your compressor as possible. The make, the model, the age of the compressor, how much it is used, the type of power supply... anything that you can think of that will help us (myself and the many visitors) help you.

Oh, and please read the existing posts below first. It is possible the answer you are seeking is already here!

And, if you've got a suggestion about solving the compressor will not build pressure problem that someone else has posted on this forum, please click the comment button on any existing post to let us all know about all about your experience.

My thanks...

Bill

Ask What to do when your Compressor Will Not Build Pressure

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Some of the reasons why your compressor will not build pressure.

Click below to see the problems and solutions when other people's compressors won't build pressure.

Won't build pressure - Leaks from a valve 
Won't build pressure after the compressor starts. Leaks from a valve on the bottom of air tank?

Centrifugal compressor not exceeding 100 psi 
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Chicago Pneumatic CPE100 won't build past 5.6 bar 
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Battery operated compressor runs but does not air up tire 
My portable, battery operated, air compressor runs, blows air out but will not air up a tire. It is rated for 150 psi. It goes to what ever the air pressure …

Porter Cable CPLKC7080V2 will not build pressure 
I have a Porter Cable CPLKC7080V2 compressor. I moved it from one shop to another. Since I have moved it, it will just run and run and not build any pressure …

Pop Off Switch not working properly 
The compressor comes on runs a few minutes, when it builds to pressure, the pop off valve pops open before cutting machine off. Switch has an OFF and …

Air compressor won't build pressure 
My air compressor gets air from the motor but don't put any in the tank.

Blackmax 5 hp about 20 yrs old - no air 
my air compressor build and holds air just fine as long as I am not using a air tool, when I use a air tool the air pressure drops instantly , I can unhook …

SIP Airmate Nimbus 50 has no pressure building at all. 
Hi, I have an SIP Airmate Nimbus 50 (model 06234) which will not build any air pressure in the tank at all. I have changed the reed valves, gaskets …

Will not build pressure past 40 psi 
harbor freight central pneumatic 2.5 21 gal vertical oil gray in color will not build pressure past 40 psi 2 valves thin strips of metal on valve plate …

Air can't get to tank 
i pull the pressure tube to the tank off and I feel it building pressure but it looks like something is blocking tank

Compressor tank will only fill a portable tank half way 
I have a small compressor and tank that has a gauge showing about 110 psi when it auto shuts off...no problem there. I recently bought an inexpensive …

Viair pumps will not build pressure 
My viair pumps will not build pressure the grounds were dirty when this happened My pumps are barely spitting air out. But my main ground connections …

Compressor will not build pressure after replacing V-pump with a new unit. 
I replaced the V type pump with a new unit after the old one seized. It came with a pipe connecting one head to the other. However the output was on …

Kargard compressor stops building pressure after about 120 psi 
Kargard compressor stops building pressure after about 120 psi... just under the PRV shut off... I have a 1960 Kargard MBI-KA60-6 256 Compressor that …

Not enough pressure to run my spray gun after one hour of use 
I have a Fini Ciao Compressor and a minijet SATA spray gun. I'm not sure I bought the right compressor for it. It works perfectly. I make it rest …

Only pumps to 20 lbs and keeps on running 
It is a small 1 horsepower 3 gallon craftsman air compressor that will pump no more than 20psi. Should I take the head off and investigate?

My compressor keep pumping up to max 65 psi and not make any more compressing. 
My compressor sudenly pump up to max 65psi and not make any more compressing pressure but keep pumping . There are only below 65 psi compressor will make …

Wolf compressor doesn't deliver enough air 
Compressor should run at 12 bar but only runs at 6.5 bar. Purchased a Wolf Compressor 100 litre unit with running pressure 12 CFM. We want to use …

my compressor goes up to 95 psi and then just shuts off 
my compressor goes up to 95 psi and then just shuts off is there a way to adjust it? it is suppose to hold 250 psi

Compressor very slow to recover to desired PSI 
Lower setting (say 40 PSI or so) to run spray gun. Sprays OK first spray then less and less pressure at gun next few sprays. Must wait 5 to 10 seconds …

Compressor will not fill up with air.  
Turned comp on for the first time only to hear air and will not fill up. I am an apprehensive female using these tools for the first time. I have …

Does not build pressure 
The other day the compressor just stopped working. We found the prongs of the power cord were "sparked." We cleaned them up and the motor turned on. …

Are worn reed valves the problem? 
if i see daylight through the intake reed valve even after cleaned is that normal or worn out. the exhaust side is fine. it builds pressure slowly …

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bergen 3hp 100 liter won't build over 45psi 
Hello I have a 3hp bergen it's only 4 years old and not used very often. It won't go above 45 it just keeps running. And it takes a long time to get to …

Should my intake valve be blowing air out ? 
I changed all the gaskets even change the oil and still no pressure. The air is blowing out the intake valve and also the oil fill cap. Did I do something …

No pressure coming out of the motor. 
Bill, I have a california air compressor model 10020. My mother bought it for me at an auction site. It is brand new out of the box. The motor runs great …

Builds up pressure to 45 psi then boggs the motor down  
compressor builds up pressure to 45 psi then the electric motor boggs down if you release the pressure at the compressor it speeds back up

Cosmo compressor runs but not charges 
i was given a 6 litre cosmo air compressor by a friend. my problem is that there is no instructions with it, so i have no idea what switches,valves, …

Westinghouse 3YC compressor - pressure builds to 25 lbs and runs and runs! 
Westinghouse 3YC compressor. I took the valves out of both sides of the heads. All the springs are intact. The springs on the high pressure side look …

Overheated head on cylinder must have lost compression  
the piston ring appears to be made from a copper ring... is there a possibility the exhaust gasket has been compromised instead? in your opinion which …

no air pressure while compressor is running 
I have a 6 gallon air compressor that I purchased two years ago. problem: when the container of oil that came with the compressor ran out, I stupidly began …

Compressor will not stop running 
The compressor will build pressure to 150psi, and will continue running. It won't get pass 150psi. I do hear air escaping when i turn it off. The …

Farm Master model A-9 won't go past 20 PSI 
My neighbor had it in her garage for 9 yrs. It runs. I put new oil in it, chk the wiring and fired it up. It will not go past 20 lbs. I also opened the …

Compressor gasket made out of pop can 
used a coke can to make my gasket job done !

Blue Max compressor will not build pressure. 
Have a Blue Max 8 gallon compressor. Only use to fill tires and ball for grandkids. It is 6 yrs. old. It will not build pressure and blows are out the …

srt model/ 1040/ 2.5hp not going above 25 psi 
Hi Bill I came across your website and I know you can help. We bought this srt model compressor 1040 / 2.5hp and it is not passing above 25psi . Can YOU …

builds only to 40 psi  
slowly builds to 40psi and stops new valve plates gaskits piston and sleeves

Air compressor stalls out 
Hi I recently switched tanks on my twin piston electric compressor. Old tank rotted out. Now, I've lined up everything, Motor, compressor and belt. …

US General air compressor will not build pressure 
compressor runs fine but will only build 45 lbs. of pressure check valve seems to work. I pulled the top plate and a piece of plastic was cought in …

Thomas Air Pac motor bogs down when trying to rebuild pressure 
Thomas Air Pac 2 HP installed #10 wire to box with 30 amp fuse-- nothing else on circuit New pressure switch new tank valve new capacitors With …

hansa htc 20a compressor leaks oil from air intake, doesn't cut out 
hi, i was looking on your site but could quite find my problem. i have a hansa htc 20a compressor. its a silent oiled compressor. The compressor …

Air compressor runs and pumps but no pressure 
Air compressor runs and pumps but no pressure? It seems to not have enough pressure from the pump to pressureize the tank took line off from pump …

Compressor purrs like a kitten but no air 
Hi Bill, My son directed me to your site.(Bob, your son is wise beyond his years! :-) B. ) Hope you can help me. I have a Charge Air Pro 3/4 HP Air …

Compressor bogs down when running 
When I turn the compressor on it builds to 20lbs and then the motor bogs down and wont kick out. There is a new pressure switch on it. They compressor …

clarke champ ac2001b motor runs tank does not fill 
this compressor has always run. suddenly the motor runs but tank wont fill. your ideas please. it is a clarke champ, 2hp, 4 gallon tank, model ac2001b. …

One compressor cylinder works one does not 
My compressor looks alot like the wards compressor in picture when tank is empty and turn it on you can feel one side sucking air if you push hard on that …

Air compressor does not kick back on soon enough 
Compressor builds max pressure then when you release air it does not come back on until like 5 mins or so why won't it come back on as soon as i release …

tank air - compressor shuts off at 110 
Say my tank is rated at 125 or 135 psi max but the compressor shuts off at 110. Why does it do that and can the tank pressure be adjusted up? If not why …

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pro air 2 air compressor builds no air 
I have a pro air 2 oil less air compressor,125 psi , when I turn it on the motor turns on but no air is being produced. Please let me know your thoughts …

Air compressor won't run an air tool or pump up a tire 
bill, to answer yor questions its a 2.5 horsepower 25 gallon comp. and i can barely put air in a tire.it says tank mp is 126psi.when i use tool outlet …

kargard air compressor just not building air pressure? 
i have a 1962 3-phase 2-stage kargard air compressor that was working fine then all at once started knocking in the pump shut it down took it all apart …

only get up to about 50 and will not shut off. 
stop when pressure got to 150 now it only get up to about 50 and will not shut off. also my hound dog chewed off the air filter. ________________ …

Compressor not building pressure - will not start 
I have a 3hp electrical oil compressor with a 5 gallon tank So Yesterday, while I was working, I noticed that the the compressor kept running for a …

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