Umarex ReadyAir portable compressor: Part 2

by Tom Gaylord
Writing as B.B. Pelletier

Umarex ReadyAir portable compressor

Part 1

This report covers:

  • Setting up the compressor
  • Setting the pressures
  • Test plug
  • Not set and forget
  • The tests
  • Test One — BSA R10
  • Bleed valve
  • Test two — AirForce tank
  • Runtime
  • Test 3 — AirForce tank outdoors
  • Summary

Today we look at how the Umarex ReadyAir portable compressor operates. I’ve devised three tests that should demonstrate the operation quite well. Let’s go.

Setting up the compressor

To get the compressor ready for the first two tests I attached the 110 volt household power cord and the flexible air hose that comes with a female Foster fitting on the end. If only all airgun manufacturers would use the male Foster fitting for all their guns the world would be abetter place!

The other end of the hose that attaches to the compressor is a properly sealed 1/8 BSP threaded adapter that has a rubber seal inside. I tightened it hand tight for all the tests and it held air perfectly.

Setting the pressures

The compressor comes with the control panel set to run in English, the pressure reading in PSI and temperature reading in Fahrenheit. The languages can be changed to French and Spanish with the push of a button. Pressure can read in bar and temperature in Celsius if you prefer.

Your first task after plugging in the compressor is to set the desired fill pressure. When the compressor gets to that pressure it will stop pumping, though if the cooling fan has come on it will continue running. You need to leave it running until the temperature drops below 87 degrees F. The fan never switches off until you push the off button.

Test plug

In the maintenance video that we watched in Part One, Rick Eutsler wondered whether there would be a test plug for the air hose in the compressors that are shipped to the public. There is one in the test compressor. It came to me plugged into the Foster fitting on the hose.

ReadyAir test plug
The ReadyAir does come with a test plug to check out the system before pumping an airgun.

Not set and forget

I told you in Part One that the ReadyAir is not a set-and-forget compressor, but I’m telling you again. However, because it operates so quickly, that really won’t be a problem for you. I had this one running in my office and could hear when it shut off. I kept an eye on the display, but that was more because I was curious than for any other reason. It’s a good thing I have to return this one to Umarex USA because if it was around my place I would never get to use my big Air Venturi compressor or my carbon fiber tanks.

The tests

The first two tests are indoors, using house current, which in the U.S. is 60 Hz 110 volt current. I’m plugged into a 15 amp outlet. Before the first test I checked the compressor with the test plug installed in the end of the air hose. The plug seals the air hose, allowing pressure to build quickly. It’s a simple test that the whole system is running as it should. I set the test pressure at 4500 psi and started the compressor. It read 72 degrees when it started, with the house temp reading 69 degrees. It got to 4500 psi and shut off in under a minute and the temperature increased to 75 degrees.

Test One — BSA R10

My BSA R10 Mark II has a 200cc reservoir. That’s 12.2 cubic inches. The reservoir gauge read 110 bar/1595 psi when I started the test and the compressor was set to stop at 232 bar/3365 psi. When it is plugged into the wall the compressor’s display lights up. That’s when you make any adjustments and set the fill or cutoff pressure.

ReadyAir R10
The BSA R10 was the first to be filled.

When you are ready, push the start button and the compressor begins to pump. Don’t forget to close the bleed valve before starting the compressor.

Bleed valve

I love the handle on the ReadyAir bleed valve. It’s large and grippy and was obviously made by someone who understands what we are doing when we bleed the line.

ReadyAir bleed valve
The brass bleed valve (arrow) is closed when the compressor is pumping. The large grippy handle makes bleeding very easy.

On a carpeted floor the compressor jiggles back and forth about a quarter inch each way with the rhythm of the pump. 

The compressor’s starting temperature was 82 degrees F. When the pump stopped pumping at 3365 psi after 4 minutes, the temperature read 120 degrees F. The fan cooled the pump back down to 87 degrees F in another 5 minutes and then I shut it off.

That’s how it went. The ReadyAir was efficient and quick to fill the BSA. Like I already said, if I owned a little compressor like this one I doubt my big compressor would get much of a workout.

Test two — AirForce tank

Now we’re going to put the ReadyAir to a real test. I took an empty 495cc/30.21 cubic inch reservoir from an AirForce Escape and attached it to the compressor. I set the fill to 3,000 psi and started her up. This time I noticed something that I hadn’t seen with the smaller BSA reservoir that was 2/3 full. The pressure in the tank would rise and then sink back down by several psi. It did that throughout the entire fill.

The compressor started at 84 degrees when the air tank was empty and 17 minutes later when it stopped pumping at 3,000 psi, the temperature was 140 degrees F. I was so faithful to time the fill with my watch, but this time when I disconnected the air tank I noticed that the display on the compressor was also timing the fill. It said the same 17 minutes I had just recorded.


The manual has an explanation of everything on the display and now that I know what to look for I see a runtime indicator. I didn’t see it before, nor was I aware it was there. Not only does it tell you what the compressor has just done, if you keep a logbook for your compressor it gives you the amount of time to enter, so you’ll know when those 20 hours are up and the maintenance cycle (piston rebuild and charcoal filter replacement) is required.

ReadyAir runtime
The runtime is the yellow numbers in minutes to the left of the max fill pressure.

So, 17 minutes is a longer time. But I went from zero psi and you won’t do that very often. You’ll go from 2000 psi and fill to 3000 in a few minutes.

Test 3 — AirForce tank outdoors

Test three is a test using the 12-volt cables attached to a car battery. I first attached the battery cables to the compressor and then clamped them to my truck battery. The same AirForce tank was used and I had emptied it all the way before this test. The battery cables are very long and the pump can sit on the ground. The manual advises that you leave the vehicle running while the compressor is running.

ReadyAir truck
The battery cables are long enough that the compressor can sit on the ground.

Obviously this test was outside, and it was in 50 degree F weather. Umarex says to operate it in the shade if possible, to keep it cooler. The pump never got above 105 degrees F in the 18 minutes that it took to fill the tank and shut down. The temperature of the compressor dropped below 84 degrees within five minutes after the pump stopped but the fan kept running. I then pressed the on/off button and the pump started as the entire compressor shut off. It’s a strange sensation, but the pump stops right away when the off button is released.

This was a second test of filling from empty. Normally a tank this size will take 6-8 minutes to top off becauise you will never go below 2,000 psi.


What more can I tell you? The ReadyAir runs just like it should and the fill times are relatively brief. The instructions are straightforward and everything you need comes with the compressor.

I think the ReadyAir gives us a reliable and supported air compressor at an affordable price for many more airgunners.

Umarex ReadyAir portable compressor: Part 1

by Tom Gaylord
Writing as B.B. Pelletier

Umarex ReadyAir portable compressor

This report covers:

  • The price
  • What about eBay compressors?
  • What is the ReadyAir?
  • Set but don’t forget
  • The noise
  • The connectors
  • The test
  • Maintenance
  • Summary

Today I start looking at the Umarex ReadyAir portable air compressor. When Umarex sent me their press release on the second of December, I asked specifically to be able to review a media sample. I did that for one simple reason — the price.

The price

Yes, it was the price that attracted me to the ReadyAir. At the SHOT Show last January they hoped it would retail for $500, which is a killer price. It’s gone up a little since then, but not that much. It’s now retailing at $550, but I see that Pyramyd Air has already deflated that a bit.

Why am I so impressed by the price? Because if Umarex stands behind this compressor it should work as advertised. And today I’m going to tell you some nice things about the scheduled maintenance Umarex recommends that supports that notion.

Price has been a deterrent to a great many people who want to get into precharged airguns. They are stopped by the apparent lack of an affordable high-pressure air supply. The air rifles themselves have decreased in price over the past 15 years until now you can buy a rifle with a lot of desirable features for under $300 — the price-point PCP (PPP)! But, other than a high-pressure hand pump, there has not been a good way to get air into those rifles for less than an outlay of twice what the rifle costs.

Not everyone is willing or able to use a high-pressure hand pump. That’s what make an affordable small compressor so desirable.

What about eBay compressors?

Yes, there are cheaper high-pressure air compressors. You’ll find several on eBay for prices that seem impossibly cheap. Are they any good? I really don’t know because I haven’t tested any of them. Reader GunFun1 has had one or two and sometimes talks about them, and that is the limit of my exposure. People believe that if something sells for very cheap, the seller is forgoing all the expenses of a storefront, advertising and such. That’s true but it also means they can pull up their tent stakes at any time and leave you holding the now-expensive and non-functional bag.

The ReadyAir, in contrast, is backed by Umarex USA as well as by Pyramyd Air, which means that parts and service should be available for a long time. Of course the ReadyAir is also made in China — as are most of the affordable air compressors for airguns these days. But when a company that has a reputation to protect gets into something like air compressors, they make certain there aren’t going to be any quality issues up front. And when there are, because stuff always happens, they are right there to resolve it with you! That and maintaining a strong support chain adds cost to the unit.

There are seals in a high-pressure compressor that the Chinese can put in but up to this point I don’t believe they have. Even Crosman and AirForce Airguns, who both developed small compressors, ran into this problem. A compressor is something you simply cannot beat down to a price and expect it to hold up.

What is the ReadyAir?

The ReadyAir is a portable high-pressure air compressor for filling airguns. It fills to pressures up to 4,500 psi, which makes it ideal for many PCPs that have come to the market with fill pressures above 3,000 psi

The ReadyAir is made to fill airguns — not larger air tanks. However, Umarex does give the times it takes to fill a 13 cubic-inch tank, such as found on the Gauntlet (0-3,000 psi in 7 minutes), a 17 cubic-inch tank like the one on the AirSaber (0-3,625 psi in 11 minutes) and a 32 cubic-inch tank like you find on the Umarex Hammer (0-4,500 psi in 27 minutes).

The ReadyAir is portable. It weighs 26.5 lbs. without the cables and hoses. A handle on top makes it easy to carry. It is an oilless compressor, which means the required maintenance is low, but heat is something to watch out for. So the compressor shuts off if the operating temperature is exceeded. It also has a 40-amp fuse to protect the internal circuitry.

The ReadyAir operates on either 110V household current or 12V car current. The company advises you to leave the car running when you fill that way. The compressor  is air-cooled, so there is no water to worry about. Louvers on all sides of the case allow for air circulation and Umarex advises to run the compressor in the shade if you’re outdoors. And leave some space around the unit if you’re running it indoors.

Set but don’t forget

The ReadyAir has a single control panel that shows and runs everything. It can be set to show English or Spanish. The temperature display can be set to Fahrenheit  or Celsius. And the air pressure can be shown in psi or bar. You can set the air pressure at which the pump stops pumping, which would normally be the max. fill pressure of the gun you’re filling. You can set the temperature at which the pump will cut off, which can be set as high as 160 degrees F, and no higher. At 87 degrees F the internal fan will start and it will run until the temperature drops below 87 degrees F. So when you finish filling a gun you can bleed the line and disconnect the gun but leave the fan running — i.e. don’t unplug the pump until the fan stops. If the ambient temperature is above 87 degrees, allow at least 15 minutes of cooling before you pull the plug.

ReadyAir display
The display with the compressor under no load.

Umarex says to stay by the compressor while it runs. That is, don’t set it and walk away. Since it is only filling airguns that shouldn’t take too much time, because we don’t shoot them down to empty. So, the times listed above will be less in the real world.

The noise

The ReadyAir is not as quiet as other small compressors I have tested. But it’s quieter than a full-sized compressor that will fill a large tank. Under no load it registered 86.3 decibels on my sound meter. That’s too loud to have in the same room if you expect to converse, so I think the garage or utility room is the place to run it.

ReadyAir sound
The microphone was held 3 feet from the compressor for this reading (left number, only).

The connectors

The compressor comes with both a 110 volt house current cord and 12-volt cables for a car. There is also an air hose that terminates in a female Foster fitting.

ReadyAir connectors
All the cords, cables and hoses you need come with the compressor.

ReadyAir ports
All the connection ports and terminals are in the same place on the compressor.

The test

I will test the compressor both indoors and outside. I will time it filling an airgun of known size. But that’s as far as I can take it.

If you want to know how long it will hold up under such-and-such an ap-plication, I can’t tell you. For that you will have to watch the comments as they come in. And longevity is the true test of these smaller compressors.


The compressor comes with a replacement 40-amp fuse and it is recommended that you keep several around to use when required.

Every 20 hours of use it is recommended that you replace the high-pressure piston rings and seals. Umarex provides an excellent 22-minute video that shows how to do this. I recommend to everyone considering buying one of these ReadyAir compressors to watch the full video, because it shows you an in-depth look at what keeps the compressor operational.

It takes a long time to put 20 hours on this compressor. Remember, this compressor fills a typical air rifle in a few minutes. Many shooters will use it for a year or more before the first rebuild is required. The compressor comes with all parts necessary for one rebuild.

Every 20 hours it is also recommended that you replace the compressed activated charcoal filter. That is held in by one Allen bolt and is spring-loaded for easy removal. A replacement filter comes with the unit. This is covered in the manual.


The ReadyAir is the lowest-cost high-pressure air compressor on the US market that has factory support. Will it change the face of airgunning in this country? Probably not. But with the push the PPP gave in 2017, this is another big shove in the right direction!

When the fix is so simple it’s difficult to see

by Tom Gaylord
Writing as B.B. Pelletier

This report covers:

  • The start
  • Owner’s manual a bust
  • Here he comes to save the daaaaay!
  • Duhh
  • Call a real man
  • Once upon a time…
  • … presto!
  • Manuals and aftermarket support
  • Analysis of the problem

Most days my blogs come from tests of airguns, ammunition and shooting equipment. They are straightforward and unfold in familiar ways. But ever so often a blog idea jumps up in my lap and licks my face like an excited puppy. That describes today’s report.

The start

It all started about 3 weeks ago when I went to fill my carbon fiber air tank, using my high-pressure Omega Supercharger compressor. I flipped the start switch and the fan came on but not the water pump. The Omega Supercharger is water-cooled and has numerous safety features built in. One of them is the compressor pump will not operate if the water pump is not on. That’s so the compressor pump will always be cooled — a reliability feature.

But now my water pump wasn’t coming on and I had to sort it out. That has happened several times in the past after the compressor has been transported any distance in a car, but I was always able to get it started eventually (meaning in minutes). This time was different.

Owner’s manual a bust

The owner’s manual that came with my compressor isn’t of much use. You basically have to know how to operate the compressor to make sense out of the instructions. And, no, there is no schematic!

I played around with the various safety switches and electrical connections for several days before calling my gun buddy, Otho, for assistance. I thought he might swoop in and fix it with a glance, like he sometimes does with other things that puzzle me.

Meanwhile I took my carbon fiber tank over to AirForce and asked them to fill it with their industrial compressor. It took that wonderful machine only 10 minutes, but the drive over to the plant and back was why I got a compressor of my own.

Here he comes to save the daaaaay!

Last Thursday Otho came by with his multimeter and we took the access panels off both sides of the compressor. I had hoped to find a loose wire that could be attached to an obvious connection, once the insides were exposed. Alas — no luck! Lots of wires, but none that were loose.

Next, we traced the wires from the front panel, where the names of the switches they are connected to told us their functions. Again no luck. I am going to show you a picture of the back of the panel, so you can see what we saw.

back of panel
Lots of wires that all have to be checked at both ends! This is not as simple as I hoped.

I pulled on every wire at both ends, hoping to find a loose or broken connection. Again, no luck. Everything is wired well and all the wires seem to be doing their jobs.


By this time I had spent a couple hours looking at the compressor and Otho had spent nearly an hour of his time, as well. We decided that the next thing should be a continuity check of every wire in the cabinet — hence the multimeter.

If all of this sounds involved, that’s because it is! Very involved! But how else are you going to do it? How else, indeed!

We put off working on it that day, but knew we’d have to tackle it real soon.

Call a real man

Otho and his wife were over at my house to watch a movie Sunday evening and one of their friends called. He wanted to take them to dinner but when he got to their house they weren’t there. So he came over to my house, and that’s when the lightning bolt struck! Otho’s wife, Marsha, said, “Why don’t you ask Joe to look at the compressor?”

Otho burst into a smile that threatened to separate the top of his head from the bottom. Joe, you see, knows about stuff — stuff Otho and I just putter around with.

Once upon a time…

Actually, war stories don’t begin that way, but this is a family blog and I can’t write the real lead-in for my war story. Other than the intro, though, war stories and fairy tales are exactly the same.

… presto!

Joe looked at the compressor while I described its operation. Then he looked at the transparent water hoses in the back of the cabinet and noted the large air bubbles above and below what I think he called the water pressure sensor. Then he said, “I think it may be vapor-locked.” Instantly I was transported back to the summer of 1955, standing on the side of the road with my father and mother and sisters, next a hot 1953 Chrysler that had vapor-locked. I knew he was right!

water hoses
Large air bubbles that were in the two transparent water hoses (were the arrows indicate) were the clue for Joe that the compressor water pump was probably vapor-locked).

heat exchange
The other side of the compressor cabinet holds the heat exchanger where the fan cools the hot water. More transparent water hoses. Now, I know why they are transparent.

“I can hear the pump trying to run but it has no water to push. I think if we just turn the compressor upside down so these bubbles go back into the holding tank, the compressor will run again.” So he did. And it did. And that’s my little story — almost.

Manuals and aftermarket support

This was not a report about an air compressor. They are all different and each has its unique operating quirks. However, by a strange coincidence, Otho’s wife brought me a manual for a Freedom8, a simpler version of the Freedom F10 Shoebox compressor on this same Sunday evening. After spending time trying to fix my compressor, I was pleasantly surprised by this manual. It seems to be very well written and would be a great help to anyone with a problem like mine.

And here is today’s lesson. Manuals and after-sales support are far more important than people think. Sure, with certain kinds of products you don’t really need them. I mean, who needs a manual for an icecube tray? But when equipment becomes complex, users often need the technical information that should go with it to operate it properly, and to know what to do when it quits. Sometimes calling the manufacturer is impossible and the importer may be difficult to contact. That’s when good information comes into play.

Analysis of the problem

My specific problem (what caused the compressor to quit this time) is I don’t use my compressor often enough. I might fire it up once every 6 weeks, and this time it had been more than 3 months since I last used it. In that time, some water will evaporate. By simply turning on the water pump and running it for 30 seconds every week, I can probably keep all bubbles out of the water lines and avoid ever having this problem again. That’s the kind of stuff that needs to be in the manual.