by Tom Gaylord
Writing as B.B. Pelletier

Today’s report is written by reader Ian McKee, writing as 45Bravo.

The world is shifting over to precharged pneumatics (PCP) in a big way, and that means more of us are needing compressed air. 45Bravo got an Omega Supercharger air compressor that had a couple issues from just sitting around. Today he tells us what he did.

If you’d like to write a guest post for this blog, please email me.

And now, over to you, 45Bravo.

Omega Supercharger
Omega Supercharger.

This report covers:

  • It works-sort of
  • Talk to Todd
  • Bag O’ Spares
  • Progress
  • Photos
  • Basic trouble shooting
  • No lights
  • The lights are on, but the compressor won’t start
  • Compressor not building pressure
  • Pressure gauge/auto shutoff
  • Bleed valve service
  • Water pump not working
  • Air/water separator auto purge system
  • The main piston assembly
  • Maintenance

So, you bought a PCP compressor that has been sitting in a closet for 4 years, what should you do? That’s exactly where I found myself.

Even though this is about the Omega Supercharger, many of the things that need to be checked or changed will apply to other brands of PCP compressors.

It works-sort of

When I got it it ran, it pumped air, the water pump worked. But since it had been sitting without being operated for so long, what had possibly gone wrong that needed to be addressed?

Mine would not build pressure past 1700psi, so I knew I had a significant leak somewhere. After some searching and spraying some soapy water I found the air/water separator/auto purge system was not sealing completely in the closed position, and was leaking from the vent line. I will go through the rebuild of that in a moment.

Talk to Todd

After talking with Todd, the support technician for Omega, the pump system needs to be used regularly, or the o-rings will dry out and need service. So if you are not using it regularly, just run it for 5-10 minutes every couple of weeks or so.

Bag O’ Spares

When you bought the compressor, there should have been a bag with spare o-rings, a burst disk and other parts. This compressor was one of the first produced, in 2014, and it was not shipped with the parts kit.

If you have lost yours, the entire replacement spare parts kit is available for $65.

If your main piston is leaking, parts for that are in the spare parts kit, but if you don’t feel qualified to rebuild it, Omega offers a piston rebuild service for $150, and they pay shipping back to you.

Since the system has a port to lubricate the main piston and o-rings during use, the main piston o-rings in mine were well lubed and still functional. But we are airgunners; we can swap some o-rings can’t we?


After fixing the air/water separator, and the compressor was able to get above 4000 psi, I found that some other o-ring rings in the high pressure system had dried out and were leaking, so we will go through each part as to what needs to be done, how to do it and some tips on things to look out for.

Remove the 6 Phillips head screws on each side of the compressor’s side covers; the shorter screws go in the bottom of the covers.

Tip: The heads of the gold-colored Phillips screws damage easily so be careful, I replaced the screws with stainless steel Allen head cap screws from Home Depot. They are size 10-32. The shorter ones are 1/2-inch and the longer ones are 3/4-inch.


TAKE PHOTOS OF EVERYTHING before you start. Especially photograph the electrical connections to the parts, and their places where they connect to the control board.

TIP: The flexible high pressure hoses have a fixed end on one end. Tighten this end first. The other end of the hose that has a female end should to be tightened last.

The o-ring sizes are not listed in the manual, nor in the parts breakdown, the o-rings that I used to replace the ones on the ends of the flexible and fixed high-pressure lines were a size 008.

Basic trouble shooting

No lights

The lights are on, but the compressor won’t start

There is air in the flow switch. Make sure there is water in the tank, and no air in the lines.
Wires from the flow switch may be loose.
More on this is covered below.

Compressor not building pressure

Make sure the bleed screw is tight, as the compressor builds pressure, you may have to tighten it more.
Check the burst disk for damage; (is air coming out of the tiny hole)?
A replacement disk is in the parts bag.
Tighten the fitting to a firm snug.
Check the main check valve, (use a 19mm wrench to remove the brass fitting the burst disk sits in). Look for a burnt or dirty check valve, clean the hole where the valve is located; replacement valves are in the parts bag. Place small end of spring on valve and center it, replace the brass fitting, tighten snug.

Omega Supercharger check valve
Omega Supercharger check valve.

We will be starting with the easiest fixes and working towards the hardest. This first one is very simple, but VERY important!

Pressure gauge/auto shutoff

This gauge is used on most of the compressors that have an auto shut-off feature, so what I’m about to tell you applies to many compressors.

It only has 2 connections, one is a flexible high-pressure hose fitting with an o-ring in each end, and the other is the electrical plug that connects it to the control board.

Be careful of this connection when working on the compressor, as it is easily jostled, and the high pressure shut-off will not make electrical contact to shut off the compressor when the desired max fill pressure is reached.

ALWAYS check this connection last after working on anything inside the compressor. And test that the auto shutoff works before closing the case.

Omega Supercharger pressure connections
The high pressure air connection is shown by the pencil, the electrical connection is right above it.

Bleed valve service

Remove the pressure relief valve knob from the unit, then remove both Phillips screws holding the block in place, remove the 2 flexible high pressure hoses with a 14mm wrench or a crescent wrench. Remove the clear vent hose by depressing the blue collar and removing the clear hose.

Clean and lube everything lightly with silicone lube, put new o-rings in the connections of the high-pressure hoses, and reassemble and test.

Omega Supercharger bleed valve in
Bleed valve knob in the compressor.

Omega Supercharger bleed valve out
The bleed valve has been removed from the compressor.

Omega Supercharger o-ring in hose
O-ring in high pressure air hose.

Water pump not working

Above the water pump is a water control flow valve. If there is air in the line, it will not let the water pump run.

Make sure the electrical connection is plugged into the control board, and no air bubbles are in the line.

You can rock the machine forward and backwards, to move the water into the control valve, or you can remove the hose above the control valve and let the water flow into the valve.

If there is water in the control valve and the electrical connections are good and the pump still does not run, using a volt meter, see if 12v DC is going to the pump, if there is no voltage, check the wires and connections to the control board. If you do have 12v coming to the pump, replace the pump.

If your cooling water is cloudy, you can drain the system. Then refill with purified drinking water, NOT DISTILLED water.

Omega also says to add 1oz. (30ml.) of regular automotive coolant to the system. If you are going to be keeping the pump in the house at room temperatures, it is not necessary to add the 1/2oz. (15ml.) of the Royal Purple additive to the system.

If you choose to include the Royal Purple additive, it is available from most automotive stores.

Omega Supercharger pump and flow valve
Water pump (blue) and flow valve (white thing above it).

TIP: when loosening the high pressure lines, use 1 wrench to hold the fitting, and the other wrench to turn the connector on the end of the high pressure line.

Air/water separator auto purge system

This was where my major problem was. Take photos of the 3 wires that connect to the black solenoid at the bottom of the air/water separator, so they can go back where they came from.

Using two 14mm wrenches, (2 small crescent wrenches will work also) loosen the 2 high-pressure air lines that attach to the bottom of the air/water separator. Be careful as there is a size 008 o-ring inside the connector of each line that will need to be replaced when assembling.

Remove the air output hose, being careful not to damage or lose the Dowdy seal (also called a bonded washer), and remove the large nut on top that holds the assembly in the case. Then remove the small Phillips screw next to it. There is a clear vent hose that is disconnected by pressing the blue locking collar back to the plastic fitting and the vent hose easily comes out.

Omega Supercharger airwater separator
The pencil points to the 2 high pressure lines at the bottom of the air/water separator solenoid, there is an o-ring in each hose that should be replaced.

Remove the black nut from the rear of the solenoid, and slide the solenoid off of the shaft, Using a piece of leather or rubber between your pliers to protect the shaft, loosen and unscrew the metal shaft from the unit, being careful of a plunger and spring that are inside the metal shaft.

Omega Supercharger solenoid 1
The black solenoid is off the air/water separator.

Omega Supercharger solenoid 2
With the solenoid off the shaft, grab the shaft with padded pliers, unscrew it and pull it out from the air/water separator. See the parts that come out.

Using pure silicone oil, clean everything, and, according to Todd, stretch the spring a little. Make sure there is no debris inside the separator, then lightly lube everything with the silicone lube and assemble in reverse order.

On the front of the case, are 2 small knobs that are used to set the purge timer — labeled as the Self-Draining Adjust Device on the pump. Set these to the minimums — every 30 seconds and the duration to 1 second, and test.

Let the compressor run a few minutes with a test plug in place at the end of the hose, and let it purge a few times. Then shut the compressor off and set the purge times and duration to your preferred schedule.

Omega Supercharger purge timer
The purge timer (Self-Draining Adjust Device) allows the user to set how often the compressor automatically blasts moisture from the high pressure air line.

The main piston assembly

It is a very lengthy, and detail intensive job.
Since I have not had to do mine (YET) I will not cover that procedure at this time.

Omega made a detailed video on YouTube that details the procedure, and you can follow that.

Or you can just ship the piston and sleeve to Todd and have him rebuild it to factory specs for $150.

His contact information is: [email protected]


When you press the power button, always make sure water is flowing through the system by looking in the sight glass on top of the case. It is a stream that is very easy to see.

If you have to go into the case for any reason, there is a plug on the right side of the electric motor that has a magnet on the end, it catches metal particles that are in the lubrication system of the motor. It is finger tight, if you haven’t done it before, remove the plug, wipe the magnet clean, and re tighten finger tight.

The first time you do this, it will be pretty fuzzy with metal shavings, due to the initial break-in of the Chinese motor used to drive the system. [Editor’s note. This is the first time I have heard of this magnetic plug in the motor. This is good information!] 

After cleaning the magnet, reinstall the cap, run the compressor for a few minutes, tipping it somewhat so the oil splashes on the magnet. Then stop the motor, clean the magnet again, then reinstall the plug and close the case.

The lubricant is Royal Purple full synthetic, and should be good for thousands of hours before needing replaced, according to the technician.

Omega Supercharger magnetic plug
Magnetic plug.

The older models like mine have a hand-turned grease screw at the rear top of the case that should be turned 2 full turns every 4 hours of operation. Watch the hour meter to know when this is.

When the screw bottoms out, remove it, add more of the supplied grease from the syringe replace the screw and turn it in until you feel some resistance.

Omega Supercharger grease screw
This shows the location of the grease screw, and the burst disk, with the check valve located under the brass fittings the burst disk is in.

Newer models have a green grease reservoir that sticks up above the case, and has an alert system that lights up when it is time to turn the grease system.

The manual says every 6 hours of operation, turn the green reservoir 1 click (1/3 turn) then push the red indication light to reset it.

Refill the grease reservoir with the supplied grease when it gets low.

Human nature is — if a screw sticking up, it needs to be tightened. Please refrain from tightening this grease screw, except at the prescribed times, as it pushes lubrication into the compressor system.

I added a piece of tape next to mine, and wrote down the hour meter number and date it was turned.

I hope this helps someone who has a compressor that is not working, or that it just gives owners a nudge on things to keep an eye out for to minimize problems.