Whether you’ve just bought a brand new air compressor and you’re wondering how to start it, or you have an old one or have acquired one from storage and you’re wondering whether there are any precautionary measures you should take when starting it up.

First of all, read the manual! If you did not get one with your unit, and you can’t find one online, then use the following information as a general guide.

Table of Contents

Starting a Brand New Air Compressor

If you’ve just bought a brand new air compressor and are wondering how you start it up, please follow these guidelines, though they’re not specific to your model, they’re a rough guide that can be of great help!

Ensure Socket Switch is Off

First of all, ensure the socket you’re going to plug your air compressor into is switched off for safety measures when plugging it in .

Fill the Air Compressor with Oil

Only if you’re starting an oil lubricated air compressor will you need to do this step, if you’re using an oil-less compressor than skip to the next!

Fill the air compressor with the suitable oil suggested by the manufacturer, to the correct level. You can check by looking through the sight glass on the sump or using the dipstick.

For information on Air Compressor Oil Types GUIDE – What Oil To Use In Air Compressor please visit our page!

Note: it’s also very important to change the oil after the first few hours of operation so remember to do this.

Plug in the Air Compressor

The next step is to plug in the air compressor directly into the power socket (do not use an extension cable, but if you HAVE to, please visit our page on What Size Extension Cord For An Air Compressor – Best Air Compressor Extension Cords).

Break in the Air Compressor

Before turning the air compressor on, ensure the drain valve is open as a very important step for any new air compressor is “breaking it in”.

To do this you should let the air compressor run for about 30 minutes with the drain valve locked open… this should be done on both oilless and oil-lubricated air compressors.

Breaking in your compressor ensures that the piston rings are properly seated and brings the bearings to be fully lubricated. Of course, this does not apply to every compressor as they may not all require a special break-in process.

Regulate the Air Compressor

Now that your air compressor is started and operating, allow the air compressor to build up its pressure. Once it has, you’re good to go and you can adjust/regulate the pressure for your specific requirements!

For further information on How to use an Air Compressor – Guide to Operating Air Compressors please visit our page!

Starting an Old Air Compressor

If you’re fortunate enough to have and old air compressor lying around. You should know that the process is not scary or complex. Simply follow the following steps!

Clean the Compressor

You need to clear the air compressor and its motor of all the dust. Air compressors when operating become very hot, and therefore will need proper ventilation to allow the heat to transfer into atmosphere.

Clean the Intake Filter

All air compressors may not have intake filters, some may have two if they have twin cylinders. Look for yours and if you have one you must remove it and replace it if it’s really dirty. For more information on an Air Compressor Intake Filter – Replacing, Locating, Cleaning & Purpose Guide please visit our page!

For the sake of the compressor test, you can leave the intake filter off, but if you’re looking to run the air compressor for a decent length of time then it would be advised to replace the intake filter.

Inspect the Air Compressor

It’s important that you spend some time closely inspecting all parts of the compressor after or during cleaning it. Look for obvious flaws, ensure all the fittings are tight, look find any potential leaks and broken components.

If you find any broken or missing parts, you must replace them before going any further in this guide!

Inspect the Power Cord

Make sure you check the electrical wiring for any damages!! You don’t necessarily know where it’s been stored… rat infestations can cause the wires to be chewed.

Ensure that the plug on the power cord end is in good shape and is suitable to be placed into a typical 120 VAC wall socket. If the plug looks unusual then be sure to investigate the information on the nameplate about the power supply for that compressor motor.

Drain the Compressor Tank

Though it may be very unusual for an old air compressor to have an air pressure trapped inside its system, make sure you check!

Open the tank drain valve slowly with care until its fully open. Even if you find no air left in the tank, there may have been water sat in the tank. If there had, it’s possible that tank-wall corrosion has begun within the system.

So when you open the valve, if red water dribbles out, this will suggest that water and rust debris is inside your tank. Do not panic, if it’s only a little, this does not mean that your tank is unsafe.

Run any Necessary Tests

If the compressor is very old and rusty, it may be worth conducting a thickness test or even a basic hydraulic pressure test on the pressure vessel to ensure it is safe to use!

Why a hydraulic pressure test? It’s a good way to test the integrity of the air compressor tank by filling it with water, and then using a hydraulic pump to force air into the full tank so that the increasing air pressure is force against the water and the tank wall.

If part of the tank wall starts to leak then you will know that it has been weakened by corrosion, typically along the weld seams.

Hydrostatic tests have much less potential energy stored in them than pneumatic tests – so it’s the safest way to test a pressure vessel. The vessel should be tested based on pressures indicated on its nameplate to mitigate risk. If in doubt at all, please consult a professional.

Check the Air Compressor Oil

Check the oil level inside the air compressor, well hopefully there won’t be any in there but if there is it will be worth replacing with new oil before starting up the machine. For information on Air Compressor Oil Types GUIDE – What Oil To Use In Air Compressor please visit our page!

You can use the dipstick or sight glass to check the level of the oil and ensure you have the right amount inside the compressor!

Start the Air Compressor

Now that you’ve done all the necessary checks and preparations you can plug your air compressor cord into the wall socket (do not use an extension cable, but if you HAVE to then please visit our page on What Size Extension Cord For An Air Compressor – Best Air Compressor Extension Cords).

Your best bet is to monitor the tank gauge, and allow the tank pressure to get to 10 PSI then shut the compressor off. Listen carefully and look carefully for any leaks.

If everything is okay, fire it up again and this time go to 20 PSI before stopping and checking. Repeat this up until you reach around 90 PSI or whatever pressure your air compressors name plate advises.

Starting an Air Compressor that has been in Storage

If you’re fortunate enough to have acquired an air compressor that has been in storage, you can follow the following steps in order to start it!

Clean the Compressor

You need to clear the air compressor and its motor of all the dust. Air compressors when operating become very hot, and therefore will need proper ventilation to allow the heat to transfer into atmosphere, if it’s been in storage then it is likely that the compressor is full of dust or dirt.

Clean the Intake Filter

All air compressors may not have intake filters, some may have two if they have twin cylinders. Look for yours on the air compressor and if you have one you must remove it and replace it if it’s really dirty. For more information on an Air Compressor Intake Filter – Replacing, Locating, Cleaning & Purpose Guide please visit our page!

For the sake of the compressor test, you can leave the intake filter off, but if you’re looking to run the air compressor for a decent length of time then it would be advised to replace the intake filter.

Inspect the Air Compressor

It’s important that you spend some time closely inspecting all parts of the compressor after or during cleaning it. Look for obvious flaws, ensure all the fittings are tight, look find any potential leaks and broken components.

If you find any broken or missing parts, you must replace them before going any further in this guide!

Inspect the Power Cord

Make sure you check the electrical wiring for any damages!! You may or may not know where it’s been stored… and even if you do, you do not know the conditions in which it has been stored… rat infestations can cause the wires to be chewed.

Ensure that the plug on the power cord end is in good shape and is suitable to be placed into a typical 120 VAC wall socket. If the plug looks unusual then be sure to investigate the information on the nameplate about the power supply for that compressor motor.

Drain the Compressor Tank

Though it may be very unusual for an air compressor that has been in storage to have an air pressure trapped inside its system, make sure you check!

Open the tank drain valve slowly with care until its fully open. Even if you find no air left in the tank, there may have been water sat in the tank. If there had, it’s possible that tank-wall corrosion has begun within the system.

So when you open the valve, if red water dribbles out, this will suggest that water and rust debris is inside your tank. Do not panic, if it’s only a little, this does not mean that your tank is unsafe.

Run any Necessary Tests

If the compressor is very old and rusty, it may be worth conducting a thickness test or even a basic hydraulic pressure test on the pressure vessel to ensure it is safe to use!

Why a hydraulic pressure test? It’s a good way to test the integrity of the air compressor tank by filling it with water, and then using a hydraulic pump to force air into the full tank so that the increasing air pressure is force against the water and the tank wall.

If part of the tank wall starts to leak then you will know that it has been weakened by corrosion, typically along the weld seams.

Hydrostatic tests have much less potential energy stored in them than pneumatic tests – so it’s the safest way to test a pressure vessel. The vessel should be tested based on pressures indicated on its nameplate to mitigate risk. If in doubt at all, please consult a professional.

Check the Air Compressor Oil

Check the oil level inside the air compressor, well hopefully there won’t be any in there but if there is it will be worth replacing with new oil before starting up the machine. For information on Air Compressor Oil Types GUIDE – What Oil To Use In Air Compressor please visit our page!

You can use the dipstick or sight glass to check the level of the oil and ensure you have the right amount inside the compressor!

Start the Air Compressor

Now that you’ve done all the necessary checks and preparations you can plug your air compressor cord into the wall socket (do not use an extension cable, but if you HAVE to then please visit our page on What Size Extension Cord For An Air Compressor – Best Air Compressor Extension Cords).

Your best bet is to monitor the tank gauge, and allow the tank pressure to get to 10 PSI then shut the compressor off. Listen carefully and look carefully for any leaks.

If everything is okay, fire it up again and this time go to 20 PSI before stopping and checking. Repeat this up until you reach around 90 PSI or whatever pressure your air compressors name plate advises.

Sometimes you may have to move a compressor from place to place. Can I lay my compressor down is a question many people ask, please visit our page for useful information on this.

If you’re having any issues while starting up your old air compressor or one that has been in storage please visit our Air Compressor Troubleshooting and Solutions page.

Or simply drop a comment into the box below with a photo if applicable so that someone can help you!