Pressure switch wiring is a smooth task unless you’re a professional. Because pros have experience. They know different compressor parts by their very definitions.
And of course, they know how these parts work. But as for beginners, they try to repair their air compressors without knowing the basics. And finally, end up with a dead weight.
In this guide, I am going to show you how to wire a pressure switch on an air compressor with step-by-step instructions.
Safety tips and warnings about different situations. So, at the end of this guide, you are ready to fix your pressure switch without any confusion in your mind.
So, here we are… Before we move towards wiring I’ll point out the list of items you need for the pressure switch wiring.
Important Tools And Accessories Needed For Pressure Switch Wiring
Below are the tools and accessories that you need and why and where you need them to fix your compressor.
The heat gun belongs to the class of versatile power tools. They are used in paint removal, welding, plumbing, bending plastic, DIY, crafting, and loosening up screws and bolts. It emits hot air usually within a temperature range of 100 to 500°C.
In our air pressure Witch wiring guide, we’ll use the heat gun for the outlet, pipe, gauge thread, and other joints. Because, in some cases, the joint due to the old compound doesn’t even move. So, the heat gun softens up the old sealant so it can easily be unscrewed.
Small Wire Brush
The small wire brush is used for cleaning out the rust, dust, and old sealants accumulated in the threads of tank pipes, safety valves, and other pipe joints.
If you don’t do it then the pipe thread sealant i.e., the Pipe Dope or Teflon Tape you apply will not be effective and the joint will not sit as tight as it should be. This can also cause the ring to become free. In the worst case, compressor air leaks.
Needle Nose Pliers
These are special types of pliers used for handling mini-jobs where our fingers can’t reach. They are mostly used for handling wiring in tight places.
Here we’re gonna use the needle nose pliers for connecting and disconnecting the pressure switch wiring to their respective terminals. Since it is difficult for our fingers to do that.
Simple Wrench Set
The simple wrench set or also known as screw wrench has specifically sized wrenches used for screwing and bolting small bolts and pipe joints.
Here we’re gonna use this wrench set for unscrewing the check valve, and tube fittings, and removing other small joints.
Ratcheting Screwdriver Set
The ratcheting screwdriver set is a multi-purpose screwdriver with different types of screwdriver bits. The bits are detachable and can be used for small screws and bolts.
Here we’re gonna use it for removing different screws and wire connections in the pressure switch.
Adjustable Wrench Or Slip Joint Pliers
The adjustable wrenches or split joint pliers are phenomenal hand tools. They have an adjustable jaw that can be used for removing and tightening up large bolts, nuts, and pipe joints.
We’re gonna use one of these to remove or tighten up the pressure gauge, pressure regulator, and switch assembly.
Pipe Thread Sealant (Pipe Dope Or Teflon Tape)
The pipe thread sealants are adhesive compounds specially used in the pipe joint threads for a tighter and more secure fit.
These sealants remove joint leakage and the free joint problem. The most commonly used pipe thread sealants are Pipe Dope and Teflon tape.
Air Compressor Pressure Switch
Choose the best-rated pressure switch for your air compressor and check your compressor manual if it’s compatible with your air compressor or not.
The reason is pressure switch comes in various types ranging from Square D, Condor, to Hubbell pressure switch also known as Furnace pressure switch.
Suppose the wires are not stripped. You have to strip them yourself. Well, I usually remove 1 inch of the insulation of the wire. You can do it according to your needs.
Solderless Ring Terminals
The solderless ring terminals work as a hook anchor system on switch terminals. They are needed when you want to replace the old pair of solderings. Most of the time you don’t need them.
Having safety gloves adds an extra layer of protection against electric shocks as well as scratches from rough, edgy areas.
If you ask me I use gloves whenever I wanna fix my compressor or verify if there is any problem or not.
How To Wire A Pressure Switch on Air Compressor?
Below are simple and easy steps that you can follow to wire a pressure switch on your air compressor by yourself.
Time Needed To Complete This Project: 20 minutes
01. List Of Tools And Accessories You Need!
Before you begin just check the tools that you need for pressure switch wiring are there on the table:
1. Heat Gun
2. Small Wire Brush
3. Needle Nose Pliers
4. Simple Wrench Set
5. Ratcheting Screwdriver Set (I prefer Dewalt)
6. Adjustable Wrench Or Slip Joint Pliers
7. Pipe Thread Sealant (Pipe Dope or Teflon Tape)
8. Safety Gloves
9. Wire Strippers (Mostly, You don’t need it)
10. Solderless Ring Terminals (Mostly, You don’t need it)
11. Air Compressor Pressure Switch (Check Compatibility)
02. You Should Wear Safety Gloves
Well, what I would recommend is to wear safety gloves as an extra layer of protection. Sometimes, you are saved from electricity but scratches are the tiny things that will get you.
03. Turn Off The Compressor
Now, you must double-check the power source. Remove or unplug the main electrical cord to avoid any electrical shock incident. Because when you are going to start wiring you have to remove the top cover of the box and the wires and terminals will be exposed.
04. Air Compressor Safety Valve Ring
Pull the safety valve ring to bleed out all the tank air pressure to avoid any problems during unscrewing and removing the piping later on.
05. Remove The Air Compressor Pressure Gauge
Now, use the wrench set to remove the tank pressure gauge. Sometimes the old compound in the thread joints and piping causes them to stuck and they won’t even budge. So, here use a heat gun to soften up the compound and unscrew the joints.
06. Unscrew The Compressor Check Valve And Tube Fittings
The next step is to unscrew the tube fittings from the check valve and pressure switch and remove the pressure switch tube.
07. Unscrew The Compressor Pressure Regulator Assembly
Now, use an adjustable wrench or slip-joint pliers to carefully unscrew and remove the compressor pressure regulator assembly.
08. Remove The Pressure Switch Cover
Use the ratcheting screwdriver to unscrew and remove the pressure switch cover. With a ratcheting screwdriver, you can change bits according to the requirement.
09. Disconnect The Pressure Switch Wires
Use the needle-nose pliers to unhook the two black wires from their respective terminals. Pull out the two big power cord strain reliefs. Now, Use the ratcheting screwdriver to unbolt and disconnect the two green wires from the pressure switch.
10. Remove The Compressor Safety Valve
Use the wrench set to unscrew and remove the pressure switch safety valve. If the valve won’t budge or unscrew then use the heat gun to soften it up a little bit.
11. Using The Heat Gun
Before you begin to remove the whole pressure switch assembly use the heat gun on the tank pipe. Due to heat, the adhesive sealant compound will soften up and you can easily remove the whole assembly without applying any force.
12. Unscrew The Air Compressor Pressure Switch Assembly
Now, use the adjustable wrench or the slip-joint pliers to turn and remove the pressure switch assembly from the pipe. It depends on your compressor’s pressure switch assembly fitting and which type of wrench or plier can easily unscrew the assembly.
13. Removing Pipe Thread Sealant
Use the small wire brush to clean up all the dust/rust or old sealant between the tank pipe thread.
14. Apply, The New Pipe Thread Sealant
Now, apply the new pipe thread sealant on the tank pipe thread for air-tight fitting. So, the ring doesn’t get free.
15. Now, Replace Air Compressor Pressure Switch
Bolt up the repaired or new pressure switch on the pipe connected to the tank. 1st do it with hands so the pressure switch can sit right on the pipe without any tilt.
16. Aligning The Compressor Check Valve And Tube Fittings
Now, use either a wrench or slip-joint pliers to tighten the pressure switch. The added pipe thread sealant will firmly lock the pressure switch assembly in its place. Here make sure to align the tube fittings with the check valve.
17. Cleanup The Compressor Safety Valve Threads
Now, use the small wire brush to properly clean out any rust/dust particles from the safety valve thread and apply the pipe thread sealant to the safety valve threads.
18. Tighten Up The Safety Valve
With sealant, the valve can sit tightly in the pressure switch. Then use the small wrench to screw up and tighten the safety valve.
19. Reconnect The Green Wires
Use the ratcheting screwdriver to remove the outer cover of the new pressure switch and bolt up the previously disconnected two green wires to their respective terminals.
Note: In some cords, the solderings are already attached with stripped wires. You just need to attach it to the terminals. But, if power and motor cords are not stripped or need stripping, then use a stripper. It will reveal the copper wires. Now, attach the solderings with these copper wires.
Advice: Well, if you ask me I only strip one inch of insulated wires in these types of cases.
20. Insert The Power Cord Strain Relief
Now insert the two big power cord strain reliefs into the side brackets. Make sure they are fitted perfectly.
21. Reconnect The Black Wires
Use the needle-nose pliers to insert the two black wires into their respective terminals of the new pressure switch. Now, use the screwdriver to bolt up the external cover of the pressure switch.
22. Brushing Up And Applying Sealant
Again use the wire brush to clean the pressure regulator threads. Apply the pipe thread sealant again to the pressure regulator’s connecting pipe threads for a snug fit.
23. Attach The Compressor Pressure Regulator
Screw the pressure regulator with your hand. Make sure the tank gauge head is facing upward.
24. Reconnect The Compressor Pressure Switch Tube
Here use the wire brush to clean up the remaining thread joints and apply the sealant. Now, use the screw wrench to reconnect the disconnected pressure switch tube with the check valve and pressure switch.
25. Tighten Up The Compressor Pressure Gauge
Again here clean the pressure gauge thread with the wire brush. Apply the pipe thread sealant to the pressure switch gauge threads. Use the same old slip-joint pliers to tighten up the gauge firmly on the pressure regulator.
26. Finally, Start Your Air Compressor
Finally, plug in the air compressor electrical cord and start your air compressor to begin your work.
A Video For Condor, Furnas & Square D Pressure Switch Wiring
Here is a video on how to wire different pressure switches. In this video, the three popular types of pressure switches are used. The Condor, Furnace (Hubbell), and finally, the Square D Pressure Switch.
How To Adjust Pressure Switch
As far as I am concerned with pressure switch adjustment. We can divide them into two types.
Adjustable Pressure Switch
The adjustable pressure switch has an adjustable screw present on it. With this, you can adjust the cut-in cut-out pressure and set the pressure differential. Such as Condor MDR-2 and Square D Pressure Switch.
In the Condor MDR-2 model, there are two large screws with large springs. Rotate these springs in a clockwise manner and you can increase the cut-in pressure. And if you want to decrease the cut-in pressure then rotate them in an anti-clockwise manner.
Non Adjustable Pressure Switch
These pressure switch types are factory preset. You cannot adjust them because the adjustment screw is not present on them. In some cases, there is a silicone seal on it by the respective company.
These types of pressure switches are auto cut-in and cut-out at a preset pressure. Such as the Furnas Pressure Switch.
How To Adjust Pressure Switch
Here is another epic video on how to adjust your pressure switch. In this case, we’re going to use a Square D Pressure Switch Type.
air compressor safety precautions
In the Instructions Section, I already talked with you about the safety tips. Before taking any action, you should know the safety tips and warnings.
I know your work is important. But your health and life are more important than the work itself. What’s the point of that work when you are going to get hurt at the end of the day? Thus, you’ll be in no shape to perform other crucial tasks in your life.
Whenever you are going to wire, adjust, or replace the air compressor. First, cut the electric supply as it is a rule of thumb.
Before you do any circuit work also turn off the air compressor from its switch. So, you can avoid electric shock or life-threatening incidents.
My advice to you is to always wear safety gloves that are shock and scratch-resistant. Sometimes electricity doesn’t get you. But, anything sharp or with a harsh surface can cause scratches to your hands while wiring and adjusting.
Air Compressor Performance
I would also recommend you check the health of your equipment. If the equipment is in a bad shape and is not able to work with the flow then don’t continue to use it. Faulty equipment is more dangerous in my book.
Air Compressor Wiring
When wiring you should be cautious. Check the wire colors and terminal labels before connecting the terminals with the respective cord. A wrong connection might cause a major malfunction or short-circuit.
Now, this one is very important. Before starting wiring or adjusting your switch, check the cords i.e., motor, power, and other circuit contacts for proper insulation. Sometimes the insulation gets damaged or melted due to excessive electricity passage.
Air Compressor Pressure Switch Wiring Warnings
Here are warnings you need to be aware of to avoid any mishap and damage.
Always, keep in mind the compatibility of the pressure switches with your air compressor. If you use a switch that is not up to the specified requirements of your air compressor then don’t use it. Check the specifications manual with the product.
Do not burden the device with excessive voltage and load more than its capacity. If you do, the switch is going to get burned. In another case scenario, the switch is not burned but its lifespan will be shortened.
Another important factor is the quality of the pressure switch. Don’t put your hand on the top of the shelf brand with sparkles.
My advice to you is to look for high-quality products with the best ratings and reviews. The brand is not going to give you anything unless the product is up to the challenges.
Another issue I have seen a lot is the leakage problem. So, check the pipes and the compressor tank carefully for any leakages before making any judgment. And if there is any leakage then fix them.
Seek Professional Help
Lastly, I would recommend you call the professionals in your area or contact the company for issues that are beyond your expertise. If you are not able to do it yourself then leave the work to the pros.
Trying to do it yourself only causes you hundreds of dollars worth of loss. It’s better to spend a few dollars and get a professional rather than lose hundreds of dollars of air compressors.
Compressor Pressure Switch Wiring FAQs
Q: How to test a pressure switch?
Ans: Below are simple steps to test a pressure switch:
1. First, disconnect the wires by pulling the wire connectors from the switch terminals.
2. Set up a multimeter to check and test for resistance (Ohms).
3. Touch the pressure switch terminals with each tester probe.
4. The multimeter will show 0 or close to 0 which indicates no resistance.
5. But, if the reading is higher then the pressure switch is busted up.
6. You have to replace or repair the air compressor pressure switch.