Air Compressor Pressure Switch for Harbor Freight

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When you get back to your compressor after a few weeks and find your pressure switch malfunctioning, you need a quick solution.

In a similar kind of situation, google infuriated me by showing some nonsense when I searched for air compressor pressure switch harbor freight. So, I am pretty confident to say that this might be the only place you will find your answers.

What I wanted is to have a replacement of the pressure switch of my harbor freight compressor. I also wanted to know how to replace that.

I had to learn it the hard way as the internet was no good. So, here is a short solution to your simple problem that was acquired from the local mechanics.

Which Pressure Switch Is A Good Replacement For The Harbor Freight Compressor?

Harbor Freight is not a concern when shopping for a pressure switch because their compressors are no different from any other compressor in the market.

They currently have compressors from these three manufacturers-

  • Central Pneumatic
  • McGraw
  • Fortress

All of them are fine with any switch that complies with the variables that matter.

So, throw Harbor Freight out of the equation so that we can focus on the real factors.

How to Find the Best Pressure Switch for Harbor Freight Compressors?

Let me repeat for the guys who are too busy to read the previous section, being from Harbor Freight doesn’t change anything in the pressure switch selection process.

The things that matter for a pressure switch are-

  • Pressure rating
  • On/off switch
  • Unloader valve
  • Number of ports
  • Nature of ports

First of all, you have to look at your air compressor manual to find the acceptable amounts of the specifications above. Then you need to look for the switch. The following explanation will help you with that.

Pressure rating

It is the range of pressure that the compressor can take. You will have two ratings here-

  • Cut in/on pressure- This is the lower range of the pressure rating where the switch starts to react to the pressure.
  • Cut out/off pressure- This is the higher range of the pressure rating where the switch will activate and stop the compressor from over-inflating.

This is the first and most important criteria you want to look for in your switch.

On/Off switch

Look for auto on/off switch. Although not the most important, it is convenient to have this feature. These switches not only stop the compression but also stops the compressor entirely.

Unloader valve

Most modern pressure switches include this feature. This connects with the bleeder line, which routes to the check valve at your tank. A tube that comes in there expels the excess pressure out of the pump head of the line so that the compressor can restart easily. An unloader valve with quick connect is even better.

Number of ports

You should go for the manifold port switches. Old style switches used to have only one port. But I suggest you buy a newer model with four ports.

These ports allow you to use accessories like the pressure gauge, safety release valve, and regulator.

Nature of ports

Most of the compressors fit with quarter-inch female thread ports. If you need a male port, then you can simply use an adapter.

A last bit of advice to end the section, always go for the most recent models of the switch even if it costs a few bucks more.

Recommendation for The Best Pressure Switches for Your Harbor Freight Air Compressor

Here are the top two air compressor switches that you can try with your machine-

  • Lefoo Quality Air Compressor Pressure Switch Control 95-125 PSI 4 Port
  • Air Compressor Pressure Switch Control Valve 90-120 PSI 240V

However, you are free to explore the market for more personalized solutions.

How to Replace, Fix, or Regulate Pressure Switch of A Harbor Freight?

Here, I will tell you a process to replace your pressure switch that is easy to understand and does not take twenty minutes to do.

These steps will also tell you how to regulate and fix certain things in the switch. You can avoid them if you don’t need them.

  1. Unplug the power unless you want to die
  2. Take off the cover from the old and the new pressure switch. You have to unscrew some screws that are holding the body in place. Then you will see six wires under three pairs of screws. A pair of them is for the motor, and the other pair is for the line/cord. These two pairs will be labeled. The two green wires and screws are for grounding.
  3. Inside the cover, there should be a sticker with the instruction for handling the inner mechanics.
  4. Regulating cut in/out pressure: There will be two screws that control the cut in and cut out pressure levels. Turning them clockwise will increase the respective pressure levels up to the limit.
  5. Unscrew all the screws and release the wires.
  6. Pull out the power lines and motor lines. There could be some retainers.
  7. Disconnect the small air line as well.
  8. Now that everything is disconnected, you need to grab the appropriate ranch and screw out the whole pressure switch.
  9. Installing the new pressure switch: Here, you have to do the opposite of the previous four steps. Screw in the switch. Pull in all the lines. Attach the green wires to the grounding screws. White wire from the motor will go to the right screw that is labeled for motor, and the black wire will go to the left screw labeled for the motor. White wire from the line will go to the right screw that is labeled for line, and the black wire will go to the left screw that is labeled for the line. Connect the airline as well and pop the cover on.

You can try to use your general knowledge to solve some problems temporarily, but most of the time, you have to change the whole switch when it shows any problem.

How to Know If Your Pressure Switch Is Defective?

Most of the time, your gut will be enough to answer that. However, some of the most common symptoms of a broken pressure switch are-

  • Not following the pressure range accurately
  • Inaccurately showing pressure measurements
  • Pressurizing so high that the safety release valve goes off
  • Electrical shocks from unexpected areas
  • Not pressurizing the tank at all

Examine the switch if you find anything like these.

Takea Glance Best Portable Air Compressor for Semi Truck Tires

Final words

Pressure switches are essentially the brains of your air compressor. But you don’t want to fry yours while dealing with it.

But I think I have covered everything on air compressor pressure switch harbor freight to keep your brain at the temperature it is. I left out the electrical switches because they deserve a post of their own.

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