I have a 2.5 40L project air compressor and every now and then it just stops and hums and so i turn it off and when the unloader valve relessers i turn it on and it goes agin, why is it doing this? it also doesn't matter were the psi is at.
An expert who has achieved level 3 by getting 1000 points
An expert that got 10 achievements.
An expert that got 5 achievements.
An expert whose answer got voted for 500 times.
Re: 2.5hp 40ltr unloader prob?
Motor stalling during the fill cycle would indicate problems with the intank check valve, weak capacitor or low power to compressor. The unloader generally opens only when compressor reaches set pressure. Easy test. Unplug compressor with air in tank and remove the small airline at the checkvalve (brass valve in tank). Listen for air leak. Checkvalve is ok if no leak at brass valve. Test capacitor for 95% rated value. Replace as needed or test for low power. Good luck.
a 6ya expert can help you resolve that issue over the phone in a minute or two.
Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of.(from cars to computers, handyman, and even drones)
click here to download the app (for users in the US for now) and get all the help you need. Goodluck!
- If you need clarification, ask it in the comment box above.
- Better answers use proper spelling and grammar.
- Provide details, support with references or personal experience.
Tell us some more! Your answer needs to include more details to help people.You can't post answers that contain an email address.Please enter a valid email address.The email address entered is already associated to an account.Login to postPlease use English characters only.
Tip: The max point reward for answering a question is 15.
If the unit comes on a builds pressure, stops normally and when the pressure drops TRIES to come back on BUT just hums, it is because the motor cannot overcome the internal pressure. This is usually because a part called an "unloader" valve has not let the pressure off or there is no unloader. If you post the model number, I can check.
This problem is caused by either the starter capacitor or the in-tank check valve. Ez to check. With no air in tank, start compressor; if motor hums or has difficulty suspect capacitor. If motor starts, partially fill tank and unplug the power. Check for air leaking at the pressure switch or air coming out of the air inlet (remove the air filter). If air leaking, replace check valve. If no air leaking, again let out all the from the tank and connect power. Allow the compressor to fill and shut-off. After the compressor fills, again listen for air leaking from the pressure switch unloader valve. If air continues to leak from unloader, replace the check valve. Good luck
There is an unloader valve and a check valve on the discharge side of the pump. The check valve is not holding and the unloader is not dumping the pressure so the compressor cannot start. Since it is new, you may want to take it back. If not you are going to be replacing parts.
If the check valve leaks, the compressor motor may not be able to overcome the back pressure within the compressor and just hum or use very high amps at start. Easy to replace with generic, usually less than twenty dollars (look on ebay or grainger.com, as factory replacement part will be much more expensive). Check fitting sizes carefully. Try cleaning the valve first. Usually debris will be trapped between the seat and valve. Debris comes from carbon deposits built up over time within the compressor or discharge tube. Be sure to clean the tube so that carbon will not enter the new valve. Good luck with your repair project.
There is not a point setting for air compressors. The pressure switch can be adjusted. Remove the cover from the pressure switch. Adjust the nut tighter for a higher cut off pressure or looser for a lower cut off pressure. It sounds like the compressor is trying tostart under load. If the unloader valve is not working, the compressor will draw excess amperage and do what you describe. The unloader valve releases the pressure in the cylinder at the end of the run cycle so the compressor can start the next run cycle under no load.
Piston air compressors have to unload to permit a restart, the two mot common types are an unloader valve or free air unloaders.
with an unloader valve this system uses a check valve mounted in the discharge line as it enters the tank, when the pump stops this check closes and does not permit the tank pressure to return to the pump. a unloader valve also opens to allow air pressure in the discharge line to vent, this valve is either on the pressure switch or on some models is on the pump, and is a centrifugal type.
Free air unloaders or head unloaders are a set of fingers that hold open the intake valves on the cylinders to permit the piston not to pump air against a head load, and once the pump is running the fingers retract to allow the pump to function as normal.
Yes, your compressor will work just fine with a Load Genie continuous run unloader from www.grainger.com. The part number is 4tk14 with a cost of about 45.00. This unloader has a built in check valve so you can remove the present in-tank checkvalve and save it for later use. All that you need to do is install the unloader at the tank and compressed air in to top of valve. (you may have to buy extra fittings to make it work with your tubing size) Adjust valve to open just before the pressure switch cut-off setting. The unloader will bypass the compressed air and will have less stress on the motor. You will not need to use the present unloader at the pressure switch. The only caution is to manually unload the Load Genie upon initial start if there is pressure in the line. Good Luck with your project.
Sounds like your unloader valve is not releasing pressure in the line to the compressor. When it shuts off after filling up if you do not here the psssht that they make when it is releasing the air in the line to the pump. then the line is still full of pressure which makes it hard for the motor to start. Check your unloader valve.
All electric compressors share a basic design with ac power pressure switch with unloader and checkvalve between the pump and the tank. When the pressure switch powers off, it unloads the compressor by releasing the air in the discharge hose. You will notice a small tire stem pin and a lever to engage it somewhere on the pressure switch. If the compressor stops before reaching set cutoff point, the air pressure remains in the discharge hose not allowing the motor to start, thus the hum you hear. Solution is to check for the proper function of pressure switch /unloader, tank check valve (if check valve leaks air back to compressor it will load motor causing hum) and extra measure check capacitor for at least 90% of rated valve. Finally, do not run this compressor with an extension cord, use more hose instead. enjoy