Carette 4500 PSI Compressor Report

1. Compressor appears well made from exterior. Mechanical load was lowered enough that even “Chinese” grade material has a chance at surviving. Cooling of components and especially that of the compressed air after each stage is impressive good. The water oil mechanical separator is big enough to effectively work. Bleeding it only costs about 30 seconds before the compressor gets back up to pressure.

2. Operation is convenient. It’s more plug and play than my Bauer Jr. The system is self contained, no need for cooling bucket hassles. You just plug it in and turn it on. Auto shutoff, PMV, auto vent all work

3. Rate is not super speedy but faster than a Shoebox. Can top off and Great White in about an hour and fill from empty in three hours. If you get the auto drain, the entire fill cycle can be unattended. The production units are expected to be slightly faster than this demonstrator and have a lower amperage draw after they replace this motor with one with a higher power factor.

4. Electrical system is fully encased. It lacks the easy, electrocution feature of the Arkansas device.

5. It came with a high pressure filter big enough to match its output. I would probably make a removable cartridge for its filter cylinder rather than put the molecular sieve and activated carbon in direct vessel wall contact – both for corrosion and ease of media inspection reasons. This component is being redesigned to integrate with the compressor’s frame. I don’t know the final configuration.

So, yes, it functions well as a high pressure compressor for filling or topping off a full size SCBA tank.

The big question remaining is whether the Carrette 4500 will survive long enough be worthwhile. No one wants to spend $1,200 on a device and have it crap out. You want a compressor that can be reasonably expected to last through years of home use. For me, that’s topping up my tank about once a month. That would be about 12 hours/year run time on this compressor.

Will it last with that level of usage? Twice that? Three times that?

How many hours before needing rebuild?
Will you run it long enough to ever reach rebuild?
When it comes time to tear down and rebuild, will there be parts available?

This isn’t over built like a “big boy” dive compressor. The construction is intermediate, but much better than the Fumigator Extreme. If it was driven hard enough to do 3L/minute, I would be worried about it breaking down. The designers have wisely reduced compression speed to about 1L/minute. That means means a lower mechanical and thermal load on the components. It has a fighting chance at a longer life span. The resultant fill speed slots neatly between a Shoebox and a big boy compressor. Pricing is substantially lower than a dive compressor – appropriate for the feature set, build level and convenient operation.

I can’t use this for a year and then report how it lasts without you guys on the forum lynching me. Bear with me. It takes time, effort, and electricity to do the test runs. Do you know how long it takes to bleed down a tank? Despite a crushing work load this month, I am building up at least 30 hours of operation before doing the tear down. That’s over two years of simulated use – long enough to give hazard a guess at how likely it will hold up. Tearing down earlier would not have addressed the longevity question adequately.

Yes, there will be plenty of pictures.

Thus far, I think it is going to be a hero. The electrical and mechanical loads are reasonable for build quality level to withstand. Speed is adequate. I’m told the motor will be replaced with a higher power factor one to further reduce amperage and slightly increase compression speed.

This isn’t a final shipping version – which is a pity since I intentionally delayed so we could get a final version. I can’t actually evaluate the oil bypass nor internal wear rate of a production unit. On the other hand, Mr Wang has been very enthusiastic about improving the product based on feedback. I had expected to evaluate a finalized compressor, not a do design consultation. Maybe the final product will end up better as a result. Even as provided, I doubt I would currently be owning my Bauer Jr if my first compressor had been this one. For a single shooter, my Bauer Jr is major overkill.

The test sample has some oil bypass, but it is at a filter manageable level. Reportedly, the actual shipped version will have a different a component that have even less oil bypass. The level of oil bypass I am seeing absolutely requires use of activated charcoal after molecular sieved drying. Also, I would NOT attempt to use silica gel as the drying agent after this compressor due to the oil inactivated silica gel. Molecular sieve is more resistant to oil. That said, it’s a small amount compared to what my Mrodair was spewing.

The configuration I received has their filter cylinder and auto drain system. I don’t know final configuration(s) and pricing. If I were purchasing one, I would definitely opt for the the auto drain because fill time is much more pleasant if you don’t have to manually bleed over the three hours needed to fill an empty Great White. For just topping off, I guess it would be acceptable to manually drain, but you’d have to baby sit the compressor. With auto drain, it’s even nicer than working with my Bauer Jr.

The water & oil separator combined PMV and very low compressed air temperature creates very effective separation efficiency. You still should use a filter, but that filter will see much less load than from a compressor without adequate separation.

The filter cylinder isn’t the final configuration. It’s getting redesigned for integration onto the compressor frame. The one I have at hand is a heavy, thick walled aluminum cylinder into which one directly packs the filter materials. Felt disks are used to keep the molecular sieve and activated carbon in place. The filter materials are in direct contact with the vessel wall. Although you could pack in a moisture indicating strip, there is no way to examine such a strip without emptying out the filter cylinder.

I would always have a high pressure molecular sieve and activated carbon filter after this compressor. Personally, I would prefer a cartridge based one to allow easier weighting and examination of the filter materials to evaluate need for replacement. Also, I’m leary of direct contact between converted C02 acids and pipe threads/walls. I guess someone could build refillable cartridge to fit inside, but that is not what comes with the compressor.

More run time needs to pass before I tear it open. I want to see how it looks AFTER it has a chance to wear. It won’t be with the production internal components, but with lower grade bearings than Mr Wang says are going into their final product. If this looks okay, then hopefully the production units will be better. That said, I can’t directly test for what isn’t in front of me.

We’re dependent on the manufacturer, but I like what I see in the overall machine design and build. The Carette 4500 fixes the worries and shortcomings that were abundant in the Mrodair Airmax compressor. It’s an entirely different level of components and build – not Bauer level, but visibly better designed than a “cheap Chinese” disposable machine.

Only three things are of concern

1. Will the small amount of oil bypass be actually reduced? This isn’t a game stopper because it is already low enough to be easily filtered. A lower degree of bypass would however increase filter material life. Reportedly the production will have 1/3 the bypass I am seeing.

2. The high pressure filter configuration has direct pressure vessel contact with the agents. I would probably opt for cartridge based filter or at least engineer a refillable cartridge.

3. Total lifespan of the compressor isn’t known. We can guess after some more hours run time and tear down. This compressor’s reasonable mechanical load and operating temperature of the unit suggest it could last longer than a higher stressed unit, but that’s not the same as knowing your Bauer comes from a line of machines with decades of long running life.