My initial thoughts on my new compressor

[jlcnuke]

Those saying the mfg should pay for your tank cleaning are nuts. I ma not aware of any company that compensates people for the auxiliary damage from bad parts, it just doesn't happen. I understand the argument but it is too much liability for companies to support things beyond their own stuff......

It is commendable to work with the supplier instead of demanding it be returned, you should do that to some extent since you would expect they know their product and it could be a benign assembly issue fixed with parts. Keep in mind the limitation on disputing the charge on your CC. This may be your last line of defense and you should not let your cooperation with the distributor go beyond this point since you will be totally at their mercy after CC protections run out. My card is two months.

@iain/hsm Has some valid points but some totally invalid points.

Lose bolts don't mean rework was done, this is a budget compressor assembled during a labor shortage, what can you expect. Oil in there doesn't mean that either. I receive equipment all the time. equipment is almost always run at the factory so it gets filled and emptied during test. Every so often equipment comes in and has oil, it is just someone forgetting to empty it after test.... (labor shortage, rember? )

Recently, i have seen 5, 75HP motors from a top tier mfg, burn up in the first week of operation because someone on their line did a **** job assembling. Given the current situation it is pretty safe to assume it was a new guy hired because he showed up.

What I can agree on is that your comp probably is flawed, and oil in the separator is a huge sign of a major flaw, not O-rings or some filter cap issue.

There is a reason Bauer gets the money they do for equipment, this thing just doesn't happen with them because they spend more on production. Nothing wrong with the bargain guys stuff, especially for non professional use, but realize what you are dealing with and react appropriately. If they offer an exchange, I would ask that they refund the first and let you order another so you have a fresh charge on your card so the protection clock starts over. My guess is that they will oblige

Just my opinion, Good Luck.

I've red enough of Iain's posts to just ignore anything he says regarding anything Coltri, as it's clear his opinion is simply that anything less than a $5-10k compressor is a complete waste of time for everyone on the planet, because if you accept less than amazing production then you're clearly going to die, despite the tons and tons of people using Coltri and similar compressor's out there. There's a reason I'm not bothering to reply to him, it's useless for someone like me (who has accepted that I'm buying a compressor that will deliver breathable air, though not be as nice as much more expensive models and will require more frequent maintenance) to bother as that's a premise he has clearly rejected as a possibility for someone to intelligently conclude (though I'm guessing the compressors I worked on in the Navy providing breathing air gave me a pretty good understanding of compressors myself, along with a reasonable amount of intelligence regarding what is or isn't an acceptable risk to me).

Would I have been happier had Nuvair offered to reimburse me to get the tanks professionally cleaned and inspected (which in reality cost me and my dive buddy some of our time and maybe a dollar worth of cleaner, hot water, plus some clean compressed air)? Sure. Did I expect they would? Absolutely not. Manufacturing defects happen all over the place in all kinds of things (even high end machines). It's a fact of life and one that generally causes more inconvenience than will be reimbursed.

As a former machinist mate, and nuclear mechanic, I'm very confident that the fix the company offered is adequate (though I'll monitor the spring as I'm concerned it may fail prematurely due to the additional compression, easy fix though if it does become an issue in a couple hundred hours). There is no evidence of any carry-over with the new cap installed and the air now seems to be coming out perfectly. I'll post up some air tests once I get the results back. For now, like the overwhelming majority of Coltri compressor owners (from what I've seen), I'm content with my purchase.

From the posts here, I'm sure some viewers of this thread would demand a refund of their money if they purchase a car that had any sort of recall on it as well, but I'm just not that kind of person when the company makes reasonable steps to correct a problem for their customers (which happens to pretty much every company that makes anything eventually).

 

[cathal]

I've red enough of Iain's posts to just ignore anything he says regarding anything Coltri, as it's clear his opinion is simply that anything less than a $5-10k compressor is a complete waste of time for everyone on the planet, because if you accept less than amazing production then you're clearly going to die, despite the tons and tons of people using Coltri and similar compressor's out there. There's a reason I'm not bothering to reply to him, it's useless for someone like me (who has accepted that I'm buying a compressor that will deliver breathable air, though not be as nice as much more expensive models and will require more frequent maintenance) to bother as that's a premise he has clearly rejected as a possibility for someone to intelligently conclude (though I'm guessing the compressors I worked on in the Navy providing breathing air gave me a pretty good understanding of compressors myself, along with a reasonable amount of intelligence regarding what is or isn't an acceptable risk to me).

Completely agree

For now, like the overwhelming majority of Coltri compressor owners (from what I've seen), I'm content with my purchase.

Bought my electric MCH6 eleven years ago, it is used to pump a 100 litre airbank, nitrox, air and trimix with no issues at all. Only time there actually was an issue was my fault as I left it running non stop for 2 hours, and the switch capacitor blew, they are not designed for running that long without a break but it was an easy fix. All I have ever done with it is change the oil and HP filter at the recommended intervals and she has been faultess.

 

[jlcnuke]

Follow up from my previous post with gas quality issues due to a bad filter housing manufacturing defect with the MCH-6:
Nuvair supplied the replacement part to fix the issue with filter housing. I cleaned everything (tanks, hoses, etc.) then let the compressor run out for a bit before starting to fill anything after that. I felt pretty confident it was going to be fine and resumed filling tanks.
To be sure it was fine, however, I sent an air sample off for analysis at about 90% filter life (as per the moisture indicating strip that I plan to use for determining if it's time to change filters - assuming no issues noted), I asked for them to check it to both Grade E and O2 compatible air standards (Coltri/Nuvair doesn't represent the compressor as O2 clean, but I wanted to know if it was coming out as such). The results are in and it passed for both specifications.
So everything looks to be doing quite well.

 

[Tony Pr]

Thanks for the thread, nice to watch the progression.

 

[PBcatfish]

What should I say, you bought an MCH6 instead of spending the bucks on a Bauer. I hope that you have good luck and never regret your decision, but that's a decision that I would have never made.

Michael

I am currently considering buying a Coltri. A Bauer is also an option. Please list the reasons for your opinion. They may help me to make a better decision.

 

[PBcatfish]

...
Keep in mind this is not really a totally legit compressor mfg, they are copying designs and having it made inexpensively in china. I'm not going to tell you how to assess risk but poor quality should be assumed from these types of companies. If you return it, you can get a new one that got assembled correctly/ doesn't have any bad parts. Plenty of people have success with these so swapping it out now will be easy and you can probably rely more confidently on a unit that works proper out of the box.

I have seen the Coltri sell for about $3k. I have seen a knockoff on Ali Express for about half of that. Coltri posts a video of the compressors being made at their production facility in Italy. Having worked in Italy myself, the video looks convincing to me.

Do you have reason to believe that all the compressors sold under the Coltri name are actually Chinese?

 

[PBcatfish]

...(Coltri/Nuvair doesn't represent the compressor as O2 clean, but I wanted to know if it was coming out as such). The results are in and it passed for both specifications.
So everything looks to be doing quite well.

I have been researching this compressor, with the intent to buy. I remember reading that it was rated for up to 40% O2

 

[Tracy]

I am currently considering buying a Coltri. A Bauer is also an option. Please list the reasons for your opinion. They may help me to make a better decision.

The MCH6 crank bearings ride in the housing. The compressor is disposable, not rebuildable. They don't use rod bearings, they use rod bushings. They are a cheaply built compressor made to a price point.
An MCH13 isn't a horrible compressor, it is a good compressor for the money. But to compare it to a similar sized bauer is hilarious.
If you are looking for something around $4000, a used properly working bauer or mako is leaps and bounds better than a new coltri.
These are my opinions as someone who works on them. They are worth the price you paid for them.

 

[PBcatfish]

The MCH6 crank bearings ride in the housing. The compressor is disposable, not rebuildable. They don't use rod bearings, they use rod bushings. They are a cheaply built compressor made to a price point.
An MCH13 isn't a horrible compressor, it is a good compressor for the money. But to compare it to a similar sized bauer is hilarious.
If you are looking for something around $4000, a used properly working bauer or mako is leaps and bounds better than a new coltri.
These are my opinions as someone who works on them. They are worth the price you paid for them.

Thank you for the reply.

I watched some service videos on the Coltri. The removable plate that housed the crank bearing attached to the block with a large pilot diameter & a flange bolt pattern. I've had good luck with that configuration in a large number of gear boxes. I saw roller bearings in the #4 cylinder con rod, where it goes to the crank. Is the bushing around the wrist pin? I didn't watch the videos for cylinders 1-3, so I don't know what they had for bushings or bearings. Parts seem available, including blocks. Top end rebuilds are scheduled at 500 hours, so I was expecting it to be only moderate duty.

My usage would mostly be filing 80cf AL tanks @ 3,000psi, Some LP steel 72s, Occasionally a couple of HP120s @ 3500psi and occasionally a 2L 4,500psi tank for non breathing use. I would not expect to do more than 4 fills in a single day ever & I would probably expect to average 4-6 fills per week. Some day, I may do some partial pressure blending, but that is not likely in the near future. I need to buy some kind of compressor because I can't find any place locally to put much more than 3,600psi in that little 2L tank & I really need it up over 4k. I could get a crappy little Hang Seng for the little tank (of non breathing air) but blowing $400-500 on that seems silly if I could put the money towards something that would also fill my dive tanks.

I have an old Bauer Utilis (late 1990s) that is probably too far gone to save. It came off of a yacht and was given to me. The hour meter shows over 4k, The PO filter housing is frozen shut to the point where Kroil & a pipe wrench can't get it apart (and it's probably past its expiration date anyway). The electric motor needs to be rewound. When I spin the compressor by hand, it does not seem to build pressure. Quite frankly, I see very little there to salvage. This has me looking for another option.

My interest in the Coltri began because they are a 4 stage pump, rather than a 3 stage, and the price looks good. I now have found that availability is also good. My mind is far from made up & the information you provided helps me. Again, thank you for that.

Do you have an opinion on the value of a 4 stage compressor compared to a 3 stage? Is that worth chasing? Or is the heat dissipation thing not as bad as I am thinking it might be?

 

[Tracy]

I have an old Bauer Utilis (late 1990s) that is probably too far gone to save. It came off of a yacht and was given to me. The hour meter shows over 4k, The PO filter housing is frozen shut to the point where Kroil & a pipe wrench can't get it apart (and it's probably past its expiration date anyway). The electric motor needs to be rewound. When I spin the compressor by hand, it does not seem to build pressure. Quite frankly, I see very little there to salvage. This has me looking for another option.

My interest in the Coltri began because they are a 4 stage pump, rather than a 3 stage, and the price looks good. I now have found that availability is also good. My mind is far from made up & the information you provided helps me. Again, thank you for that.

Do you have an opinion on the value of a 4 stage compressor compared to a 3 stage? Is that worth chasing? Or is the heat dissipation thing not as bad as I am thinking it might be?

The fact that your Utilus has 4k hours means something. Yes, it may be shot, but it is also rebuildable and it has lasted 4000 hours. Find an MCH6 with comparable hours. I think you would be hard pressed to find one that hasn't shaken itself apart.
As for the 3 vs 4 stage, Yes, heat disipation will be better with a fourth stage. Does it really matter? I don't know. Coltri only runs 3 stages on the 8-18. Bauer only runs three stages on their smaller machines. It seems to work. I have a 4 stage bauer and a 3 stage mako that run beside each other. Both are 8 cfm pumps. Final stage head temps run about the same at similar pressures.
The downside of used is you have no idea what you are getting and who maintained it with what budget. For that reason, I see the appeal of new.
That said, you can buy used with a history or a reconditioned unit.