Pressure switch wiring is a smooth task unless you’re a professional. Because pros have experience. They know different working parts by their very definitions.
And of course, they know how these parts work. But as beginners, they try to fix 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.
There is a whole bunch of problems related alone to the pressure switch. I’ll also be discussing them in my future posts. But for now, we’ll stick to the scenario at hand.
So, here we are before we move towards wiring I’ll point out the list of items you need for the pressure switch wiring.
Items You Need For Pressure Switch Wiring
Air Compressor Pressure Switch
Choose the best-rated pressure switch for your air compressor. Also, confirm if it’s compatible with your air compressor.
Wire Strippers
If 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 need.
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.
Screw Driver Set
The screwdriver set is one you’ll need the most for tightening and loosening up the terminal and other screws.
Safety Gloves
Having safety gloves adds an extra layer of protection against electric shocks as well as scratches from rough, edgy areas.
A Good Conditioned Air Compressor
And of course a good air compressor from a trusted company. Sometimes, the pressure switch is fine. While your compressor has quality issues. So, also verify your compressor performance and behavior.
How To Wire A Pressure Switch on Air Compressor
Below are general instructions that apply to all types of air compressor pressure switches.
Time Needed To Complete: 30 minutes
1. List of Tools You Need For Pressure Switch Wiring
1. Screwdriver Set (I Prefer Dewalt)
2. Safety Gloves
3. Wire Strippers
4. Solderless Ring Terminals
5. Air Compressor Pressure Switch (Check Compatibility)
6. Air Compressor (Make Sure Your Compressor Doesn’t Have Other Issues)
2. Double-Check The Power Source
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.
3. Wear Safety Gloves And Remove The Pressure Switch Cover
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. And I have to deal with these situations a lot. I hope I don’t need to explain that.
4. Check Contacts/Terminals
Check the set of four contacts/Terminals. One set of the terminal will be for the “Line/Power Cord” and the other will be for the “Motor Cord”. The wires from the Line and motor go into these terminals.
5. Check Terminal Markings
Look for markings on terminals. The companies always put labels on these types of areas so it won’t confuse the regular folks. There is a label on each terminal for line and motor cords.
6. Now, Check The Cord Color
The cords are obviously colored. Black, White, and Green. The only important thing is that the Black and white motor wire should go to motor-specific terminals. It doesn’t matter whether you put the white wire into the black’s place or the black wire into the white’s place. That’s it.
7. Attach The Right Cord To The Right Terminal
Did you remember, earlier I told you that for each pressure switch the terminal arrangement is different? You can check that mentioned in Air Compressor Pressure Switch Parts > Terminals.
8. Stripping The Wires
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, you should strip them by using 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.
9. Double-Check The Markings
Look at the markings and then loosen the screws with a screwdriver. Attach the motor cords with motor terminals and line/power cords with the line terminals.
10. The Green Wire And Screw
The green wire goes to the green screw on the metal frame of the pressure switch.
11. Start The Compressor
Put the cover over the switch. Start the compressor from the main power source.
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.
Pressure Switch Wiring Safety Tips
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.
Power Source
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.
Protective Wears
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.
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.
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.
Insulation
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 gets melted due to excessive electricity passage.
Pressure Switch Wiring Warnings
Here are warnings you need to beware of to avoid any mishap and damage.
Compatibility
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.
Capacity
Do not burden the device with excessive voltage and load more than its capacity. If you do, the switch is going to get burned. Or in another case scenario, the switch is not burned but its lifespan will be shortened.
Quality
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.
Leakages
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 cause 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.
