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A common query I see across the internet is Husky air compressor won’t start under load. This article will provide you will all the possible reasons as to why your Husky air compressor won’t restart, along with existing reader questions and responses related to the issue.

Table of Contents

Reasons Husky Air Compressor Won’t Restart

If your Husky air compressor won’t restart after it fills its air tank, it is likely that the check valve is stuck open causing the air compressor not start under load. The check valve’s role is to prevent tank air from back-flowing towards the pump. The stuck-open check valve will cause high pump head pressure, preventing the compressor from being able to restart.

Follow these steps to test the check valve:

  1. Shut off the compressor and pull the ring on the safety valve to bleed the air from the air tank until it’s empty.
  2. Turn on the compressor to fill the air tank.
  3. Bleed air out of the tank to reach the cut-in pressure, so the pressure switch attempts to restart the motor to refill the air tank.

If the compressor won’t start with air in the tank, then you should replace the check valve.

However, if the check valve is not the issue, then it’s likely that it may be the unloader valve failing. To diagnose if the unloader valve is working properly, simply listen to the compressor closely as it reaches the cut-off pressure.

Just after the compressor stops running you should be able to hear a short sharp discharge of air from the unloader valve, which is usually located on the pressure switch itself.

If you don’t hear the unloader valve releasing pressure, this could be the cause of your air compressor not restarting when there’s pressure in the tank. Visit our Air Compressor Won’t Start Under Load guide for information!

Other possibilities include the motor being too hot and the thermal overload switch not allowing the compressor to restart until it’s cooled down, or even a faulty/weak start capacitor that has the capability to initially start the compressor but not restart the compressor.

To learn more about Husky air compressors, visit our brand page here!

Reader Questions & Responses

Husky Air Compressor Will Not Restart – Husky Air Compressor Troubleshooting

Question

I have a Husky 30-gallon lay-down compressor. Model number WL651004.

The compressor upon initial start-up runs and shuts off at around 125psi.

After that while you are using it. It will no longer cycle back on.

Husky 30 gallon lay down compressor model number WL651004
Husky 30 gallon lay down compressor model number WL651004

You have to unplug it and wait approx 5-10 minutes. When you plug it back in it will run up to operating pressure and then shut off again. Only to not cycle when the pressure gets below 80psi.

I have thought that the pressure switch makes sense to be the culprit. Because it would seem that it may be getting stuck in the open position. However, I decided to post the question here for you before I purchased a new pressure switch. Especially after reading your article pertaining to how the pressure switch is not always the issue.

Response

Chris, as a comment here, could you please tell me what happens when the pressure in the compressor tank drops below the normal cut-in pressure? Does the compressor try to start and it cannot, or does the pressure just drop down past the normal cut-in pressure setting, and nothing at all happens… no clicks, no whirring, no noise?

Before you comment, check this out for me, and let me know what happens, please. When your compressor tank air fills to normal cut out watch the UNLOADER VALVE toggle on the side of the pressure switch to see if it operates. There should be a little blast of air out of the unloader valve when that happens. Is this occurring?

As another check, with a full tank of pressure, pull the plug, open a line with a valve or blow gun, or even the compressor tank drain, and slowly drop the pressure. Watch the tank gauge to see when your tank pressure is approaching a normal cut-in setting, and then pay particular attention to the pressure switch.

What do you see/hear when the pressure falls past the normal cut-in pressure setting. There should be a response of sorts and if nothing happens, then it might be the pressure switch that is the problem.

Questioner

Bill, Thank you for your reply. As far as the first question goes. When the pressure drops back down to the setpoint, nothing happens. No click that I can hear, no interactivity from the motor, etc… I will pull the cover off of the compressor this evening or tomorrow and check the valves on the pressure switch as you noted.

I will check for movement or any activity of sorts from the switch. Also when the compressor turns on and runs up to pressure. It shuts off with the slight burst of air you mentioned as it reaches its normal pressure. I will check these things and get back to you.

Thanks again.


If you have any questions regarding Husky air compressors not restarting, please leave a comment below, with a photo if applicable, so that someone can help you!