An air compressor is a valuable tool to have around, whether you use it for your work or general tasks around the house. But they also tend to be bulky and awkward, which can make storing and transporting them a little tricky. And if you’re particularly short on space, you may be tempted to lay your air compressor down or put it on its side to make things easier. But is doing so bad for your air compressor?
As a general rule you should never lay an air compressor on its side unless its brand new. New air compressors don’t typically come with oil so laying them down won’t cause any harm. Used compressors, however, will have oil in them which, if tipped over, can get into areas it shouldn’t and cause problems.
In this article, I’ll cover everything you need to know about how different types of air compressors are affected by being laid down, why it’s not a good idea to put air compressors on their side, and how to properly store and transport them.
How Air Compressors Work (A Very Brief Guide)
To understand why the orientation of an air compressor matters, we first need to understand a little bit about how air compressors work. Instead of going into the many different types and designs, I’ll just describe the basics of a typical piston compressor (the most common type).
There are two main components to a typical piston compressor – a pump and a storage tank. The pump has a piston, air chamber, inlet valve, and discharge valve. As the piston churns, air is pulled into the chamber through the inlet valve, compressed, and pushed through the discharge valve into the storage tank.
On most models, the pump will shut itself off when the tank reaches a certain pressure limit, then automatically kick back on when it falls below this limit.
Oil-Lubricated vs. Oil-Free Air Compressors
Another key aspect to understand is whether or not the air compressor uses oil. This plays a major role in whether the compressor can be tipped or laid down.
Oil-lubricated air compressors feature a sump filled with oil below the piston. As the piston churns, this “oil bath” will splash on the piston bearing and the cylinder walls to keep the parts lubricated.
These generally feature rings around the circumference of the piston that prevent oil from entering the air chamber – however, some oil may seep into the chamber in vapor form and make its way into the tank.
Oil-free air compressors, on the other hand, are designed with self-lubricating components or materials, such as Teflon. These eliminate the risk of contaminating the air with oil.
Can You Lay Down an Oil-Lubricated Air Compressor?
You should never lay down an oil-lubricated compressor. Doing so may cause oil to flow where its not supposed to be and contaminate the compressor components. It may also allow dirt and grit at the bottom of the oil sump to get on mechanical parts. However, these are not issues with a new unit that contains no oil.
Compressors with oil-bath lubrication are designed to let grit sink down to the bottom of the sump, where it can’t be splashed onto the piston or cylinder. The grit and grime will be drained away when the oil is changed as part of routine maintenance. But if the grit gets on the piston or cylinder walls, it can interfere with proper function and degrade the components. That’s why these types of air compressors are meant to be used only on level ground.
If an oil-lubricated compressor is tipped or laid down, standing it upright and letting it sit for 24 hours or more before use may allow much of the oil to drain back into the sump, but the damage may already be done – grit may be trapped in the piston bearing, oil may have leaked into the air chamber, etc. It’s best not to let this happen to begin with.
So, if you plan on moving an oil-lubricated air compressor and need to put it on its side to do so, you’ll want to drain the oil out beforehand. But even then, there’s still a chance that a small amount of oil will remain inside.
Can You Lay Down an Oil-Free Air Compressor?
You can lay down an oil-free air compressor – but it’s generally not a good idea to do so. Over time, dirt particles and condensate can form a sort of sludge in the bottom of the storage tank. Tipping the compressor can allow this sludge to interfere with certain components.
Considering how dirty and dusty workshops and garages tend to be, every air compressor has an air intake filter to help prevent particulates from entering the pump. But as this filter gets dirty or damaged over time, some particulate matter may get through and end up in the storage tank.
And as air is pressurized and compressed, it becomes incapable of holding water vapor, so the vapor condenses into liquid and collects in the tank. This is why air compressor tanks need to be drained after each use.
When the water combines with the dirt and dust, it creates a muddy sludge. If the compressor is then laid down on its side, the sludge can make its way to the tank’s check valve, which allows air into the tank from the pump and prevents the pressurized air in the tank from flowing back into the pump. The sludge will foul the check valve and prevent it from functioning properly.
Can You Lay Down a New Air Compressor?
In most cases, you can lay down a new air compressor or put it on its side with no problems. New air compressors typically don’t have oil in them, nor do their storage tanks contain any water or dirt (having never been used). However, some models come with oil installed, so always check beforehand!
Without any oil in the pump or any fluid in the tank to slosh around and get into areas where it’s not supposed to, there’s no reason not to lay an air compressor down or put it on its side for storage or transport – provided that you’re not damaging external components like pressure gauges, cooling fins, or air lines by doing so.
If you’re buying a used compressor, you probably shouldn’t lay it down. Even if the seller claims that the tank is clean and empty and the oil has been drained from the pump, it’s best not to risk it. And if you’re buying a brand new compressor, make sure it doesn’t contain any oil before you go about transporting it.
Dangers of Laying Down an Air Compressor
Now that we’ve covered what happens inside an air compressor when it’s laid down, let’s look at what kind of effects this may have.
Oil-Free Air Compressor
As mentioned above, the main concern when laying down an oil-free compressor is that any built-up condensate in the storage tank will mix with any particulate matter and slosh around, forming “tank sludge” that can interfere with the tank’s valves.
If this sludge reaches the check valve (which both lets compressed air into the tank and prevents it from leaving), it may cause back pressure to build up, straining the pump motor. This can cause the motor to overheat and shut off or burn out entirely.
If the compressor is on its side for a long period and the sludge is allowed to dry on the check valve, the flapper or ball that regulates flow may become stuck, rendering the check valve useless.
Further, the sludge may end up caking over the compressor drain valve, clogging it up and making you unable to drain the tank.
Dangers of Laying Down an Oil-Lubricated Air Compressor
Oil-lubricated air compressors carry all the same risks as oil-free compressors, with the added risk of having the oil spill into areas where it doesn’t belong.
As mentioned earlier, oil can enter the tank in vapor form, which in itself can make “tank sludge” all the more insidious. But if the compressor is laid down and oil pours out of the sump and into the air chamber, it will make matters even worse.
The oil itself can damage the inlet and discharge valves, but any grit in the oil can get into the piston bearing or between the piston rings and the cylinder walls. In either case, the result will be rapid wear and tear, or an all-out breakdown of the compressor.
How To Properly Transport an Air Compressor
As you can see, when moving an air compressor from one place to another, it’s always best to keep it upright – unless it’s a brand new model with no oil in the pump or water in the tank, in which case you can lay it on its side with minimal risk.
If you need to keep it upright, the hardest part will be getting it into and out of your vehicle. If you have a pickup truck, it may take a hoist, forklift, or ramp to get it into and out of the bed. Many people find it’s best to rent or borrow a small trailer and put the compressor on that, so they can (fairly) easily wheel it on and off with a stout furniture dolly.
The next step is to strap it down tightly using heavy-duty ratchet straps. With a large vertical compressor, this may be a bit awkward, but it’s especially important to make sure it’s secure. Fortunately, most new compressors come on a pallet to make this easier.
Alternatively, you may be able to take the compressor apart, separating the pump from the tank. This way, you can keep the pump upright to avoid oil spillage – but if you plan to place the tank on its side, make sure there’s absolutely no water in it first.
Of course, keeping a large vertical compressor upright isn’t exactly an easy task – they tend to be rather bulky and top-heavy. So it may be worth it to pay for professional delivery.
How To Properly Store an Air Compressor
When your air compressor is not in use, it’s also best to store it upright. But there are a few more steps to perform to ensure that it doesn’t become damaged in storage.
- Step 1 – Turn the air pressure regulator knob until the pressure gauge reaches zero.
- Step 2 – Unplug the air compressor.
- Step 3 – Remove any tools or hose attachments from the supply hose.
- Step 4 – Drain any excess air and liquid from the storage tank. (Place a drain pan under the drain valve and tilt the compressor so that the valve is on the bottom, then slowly open the valve and let anything drain out. Use caution, as pressure may vent forcibly. When it’s finished draining, re-tighten the valve.)
- Step 5 – Place the compressor in a clean, dry space that isn’t exposed to the elements (extreme moisture, direct sunlight, etc.). Periodically clean the surrounding area to prevent dust, dirt, or cobwebs from getting into any openings or filters.
Air compressors can be put on their sides, but only in select few circumstances. In general, it’s best to keep them upright if possible to avoid damaging any components or interfering with the compressor’s proper function.
Thanks for reading!