The last time you used your compressor, it worked fine. Now, your unit won’t start, and it’s humming. You have no idea why. But do not panic. We’re here to answer your question. Why is my air compressor humming?
We will teach you three things you need to know about humming air compressors in this article.
- What causes air compressors to hum
- How to diagnose each possible problem
- How to fix it
Table of Contents
Why Is My Air Compressor Humming?
Here are some would-be culprits that could cause the humming you hear from your compressed air unit.
The Power Supply
Air compressors need a lot of power to get started. That’s why it is better to plug them in at the outlet.
If you want to use an extension cord, try one of the short ones. With the long extension, the current has to travel a longer distance. If you have other equipment plugged into it, that may also cause the humming problem.
Helpful Tips
Not all extension cords are created equal. They cannot all carry the same workload. Ensure that the extension cord you have is fit for the job.
Unplug other equipment from the extension cord. Connect the air compressor only. That’s because compressed air units need more power to start up than they do to keep running.
Once you get it to start working, plug in the rest of your equipment.
If the hum does not stop and your air compressor doesn’t work, try another power source.
Unloader Valve Malfunction
The job of an unloader valve is the take excess pressure out of the tank. If this valve is faulty, it may cause air to remain trapped inside your system. that extra pressure puts a heavy strain on the motor.
If that is the case, the motor will not start. If the motor does not start, the air compressor will not work. Instead, you will hear a hum because there is power running through it.
Diagnosing The Problem
- Shut your unit off. For your safety, unplug it at the power source to ensure no current is running through it.
- Drain air out of the tank. Locate the drainage valve on the tank and open it to bleed the air out.
- Replace the cap on the drainage valve. Always ensure that the cap is sitting well.
- Switch the unit back on
If this troubleshooting method works, you have a faulty unloader valve. And you do not want to continue shutting off your machine every time so that you can bleed the tank.
The Fix
In such a case, the only option is to put in a new unloader valve.
Intake Filter Clogging
Intake filters in compressed air units are supposed to trap dirt and gunk. They prevent these unwanteds from entering your system. They do their job well and will continue to do so. But they can only keep work the way they should with the occasional cleaning.
If you do not clean the filters, dirt and gunk build up on them over time. This will obstruct the flow of air to the motor. Too little air causes the motor to overheat. The unit will stall and lose power. When you try to start it up again, you will hear a hum.
Diagnosing The Problem
Locate the intake filter on your compressed air unit and remove it. Start the machine again without putting the intake filter back in. You’re doing this to check whether the system will start without the filter in place.
If you get it to work again, the filter is the problem.
The Fix
To fix this problem, give the filter a thorough cleaning and put it back in your system.
Tank Check Valve
The tank check valve could be the reason your air compressor hums. The mean could mean that this valve is either partially blocked or completely obstructed.
The tank check valve allows air to pass through it from one direction. You want to find it if it is still doing that job well.
Diagnosing The Problem
- Unplug your unit from the power source
- Empty the tank as well as the PRV valve
- Take the line out of the pump head
That’s where you find the tank valve in most compressed air unit designs. If you do not know where you find the tank check valve on your equipment, consult the manual or the internet for help. - Blow air through the valve
Try blowing from one direction and then the other. Air should only get through from one side.
The fix
If no air passes through the valve from either side, it may need a thorough cleaning. Even if air gets through to one side, it may also be build up messing with its performance. Give it a thorough clean-up anyway.
If air comes through both sides of that valve, there is no cleaning or repairing it. You have to get a new one.
So, you’ve checked the tank check valve, but you still have a humming unit. Maybe the problem is the pump itself.
The Pump
Diagnosing The Problem
You can diagnose this problem by removing the pump. Getting this done could be a simple process. But that depends on the make and model of your compressed air unit. Other models might be a bit trickier. Consult your manual to find out how to remove the pump.
With the pump in hand, you can now check for any mechanical issues it may have.
If the pump cycles with ease by hand, it is not the problem. If it doesn’t, then you have the culprit causing the hum.
The Capacitor
For this problem, we will take a trip back to the beginning. I’ve left it for last because it is simpler to eliminate the other issues. If after you’ve tried all the methods above and your unit still hums, the capacitor is the culprit.
The capacitor of your compressed air unit helps your power source kick start the machine. It does so with the help of a quick-discharge battery.
If the capacitor fails, the battery cannot give the motor the extra boost to start.
The Fix
You cannot clean or repair a failed capacitor. Your only option is replacing it.
Conclusion
The best way to keep your compressed air unit working well is by taking care of it. Stick to the maintenance schedule designed by the manufacturer. You should get at least fifteen good years of service out of it.
