Monday, April 10, 2017

Carette 300 bar 4500 psi compressor review test - Part1

This is a 2 part review, in part2 of the review I will show how you can add your own PMV if you bought the standard version without PMV and autodrain.
Goto part2

My use-case for a compressor:

I need a compressor to fill up my 10L tank from 200bar to 300bar. I use a FX impact with a regulator set at 145bar. It has a cylinder of 480cc @250bar.
Time is no problem, I can wait 2 hours if needed to do the filling.
Since I am only topping up, I have no need for a PMV (in part2 I will install a bauer PMV).
I' m capable of timing 15mins to do the water draining, so no automatic stuff necessary.
I'm looking for a monthly top-up at a reasonable speed: 100bar x 10L = 1000L
I like to have guarantee for several years.
No more than 1500€

5 years guarantee on the compressor block
3 years guarantee on the electric motor
2 years guarantee on the other parts

25L/min fillrate -> 1000L should be done in 40 minutes. I can live with that.

My Compressor with the Philadelphia option ;-)


2 cylinder compressor 300bar
base model, no PMV, no automatic draining

Maintenance schedule:

maintenance part and itemmaintenance contentmaintenance PeriodRemarks
Compressor hostReplace lubricating oil for 0.3L
10-20 hours
1st maintenance
Compressor hostReplace lubricating oil for 0.3L
40-50 hours
2nd maintenance
Compressor hostReplace lubricating oil for 0.3L
70-80 hours
Air intake filtration coreCheck and sweep 
60 hours
Replace if needed
Oil-water filtration coreREPLACE
20 hours

BeltCheck and adjust
65 hours
Replace if needed
Antifreezing fluidsCheck and adjust
100 hours
replace once every 2 years

attention: only use good quality synthetic compressor oil!

Other reviews online:

an excellent 24hours torture test and tear-down:

Some collected info after my first usage. 

Important: There is NO non-return valve in this compressor configuration, so you can ONLY OPEN your scuba tank AFTER the pressure in the compressor is HIGHER than the tank you are filling! You will harm the compressor otherwise.

update 2017-04-19 : there IS a non-return valve fitted just before the oil water seperator. The manual seems to be lacking this information :)

I pumped my 10L tank from 220bar to 300bar. The compressor was first let run for 10min with no load. Total time took less than 35minutes. No exact timing, will be for the next test. I was only interested in the heat signatures.

Heat signature after 10min with no load

As you can see the first cylinder gets a lot hotter than the second stage cylinder.

Heat signature after 45min with 300bar load

The same difference in temperature is there at full load, but no abnormal temps. The cylinder-heads themselves are staying cool due to the water-cooling passing through them. The other red marking in the picture is the belt.

Temperature readings of both cylinderheads. Spot1=cylinder1 - Spot2=cylinder2

Power was between 960W and 1020W
Just checking..

Temperature of waterpump after 45min

Temperature of air after 2nd stage cooling, before entering the water-oil seperator
Cylinder heat only +3C after charge from 220bar to 300bar

2.5 ml water-oil drained from system during the 35min session

Important: After each fill you should let it do a 3-5 minute no-load run with the draining port open, to clear out any condensate water in the first cylinder!

In part2 I add a PMV to the standard model.


  1. So are you now saying that if you have the "non- return valve" (in my case I have a PMV valve), that you dont have to wait until the compressor builds pressure equal to or greater than your tank?
    For PMV starts to let air thru the valve at approx 1800 it then safe to open the tanks valve? Even if it is sitting at 3000 psi?

    1. It's best practice to only open your tanks valve when the pressure inside the carette is equal or higher.
      It is all about avoiding sudden pressure peak loads on the cylinders. In the case of a pmv, your pressure differential between your tank and opening pressure of the pmv will lighten the load versus not having a pmv at all.
      Lets say your tank sits at 3000 psi and your pmv opens at 2000psi. There will only be a 1000 psi difference. Non pmv versions will have 3 times more!

    2. nice review ... same question but i didn't understand it very well ...

      so now let say i have PMV set at 2000psi ! my tank 3000psi should i open my tank right away or i must wait until compressor equal 3000psi or higher ?

    3. You should wait until the compressor builds to the approximate pressure currently in your tank.... then open slowly...

    4. thank you for quick reply ... make more review about it , its very rare to find someone talkin about compressors

  2. After more than a year, all is still working fine and no issues at all.

  3. I concur!...It has run flawlessly! I rotate between 4 88c ft bottles, and I shoot a lot (a lot of big bore air several rifles that require 3300+ psi) issue's at all....

  4. Mine has gotten very slow, after 4000 From 4000 to 4500 can take 45 minutes ??? Any ideas ?? No leaks found. Even from zero, with a plug in the compressor line, it takes around 5 min to reach 4000 ???? Maybe have 10 hours. Royle Purple oil.

    1. Looks like a leak somewhere. Have you checked each and every connection with a leak detector spray? Also on the high pressure tubing connectors on the backside.

    2. I have a carette with 17 hours run time on it and have the same problem. IN the beginning it worked great but performance has declined getting very noticeable since about 10 hours of run time. The last time I filled my SCBA 45 minute bottle it took 1 hour to fill the last 250 PSI. No leaks.

    3. I would recheck all your fittings because it seems that you have a leak that becomes apparent only at high pressure. Have you used a leak detector spray everywhere? I have had it once when I refitted a new connector and I only found it when using the spray. Try with a plug to eliminate as much as possible.

    4. Absolutely no leaks, the belt is tight. How do I contact the manufacturer directly about honoring the warranty

  5. Do you know who the manufacturing company of this compressor is?

    1. the manufacturer is on user "sincere" sincere4500 @

  6. Am planning to purchase a fully functional Alpha-Carette compressor, Alpha air filter with necessary attachments to enable direct rifle filling, and a large air tank from Joe Brancato's Huntington Beach business location sometime soon (am hoping this week).

    Made the decision to got with this compressor instead of a Daystate 110v unit after reading an in-depth tear down and mechanical inspection of the latter after reading the review in GAT; what I read impressed me greatly, enough so to buy it.

    Want a dependable source of air to fill my pcp air rifles, specially the newly acquired ATI Nova Liberty .22 caliber rifle, whose air filling requirements exceeds even those of the .25 caliber FX Dreamline Classic, which itself taxes the capability limits of the Air Venturi Nomad am currently using.

    Am I making a good decision by going with the A-C? Certainly hope so...

    1. After 2 years still working fine without any issues. The unit maybe does not win any speed contests but it is stable as a rock and that's what I wanted.

    2. That is good to know! Am definitely buying it...