Coltri MCH22 vs Bauer IK12.14 Compressor. Which one is better?

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alanchang

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Location
Toronto
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Just an open-ended discussion. Any thoughts are welcome and appreciated. Coltri MCH22 and Bauer IK12.14 have very similar CFM and a similar price point (Bauer $5000 more but also has a lot more features). Feel free to discuss designs, longevity, and reliability.

However, MCH22 has a much larger block and a true four-stage design, rather than the double-acting second stage on an IK12.14. MCH22 also has a much lower RPM.

I found that Bauer built better than Coltri. But I only have experience with smaller Coltri, like the MCH16 and MCH6. Never had experience with the big MCH22, 30, and 36 units.

Just talk about anything. I would like to hear more about the differences. I am not making a purchasing decision since I already have the IK12.14 and I am very happy about it.

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On a more serious note it's getting more and more difficult with internet divers forums to get any real level of information in order to make an informed choice other than the echo chamber of lightweight irrelevance and opinion.

Your decision is further hampered by the lack of detailed technical information from the manufacturer and your limited option of provider being the rinky dink scuba shop in your area with their web shop buy now option.

This is further compounded by the diver him/her self being unable to understand even at a basic level of schoolboy engineering knowledge and so are persuaded either by the sales man or what the current influencer of the day has in the form or trinkets add ons and a paint coat cover.

Persuasion coercion domination with a blend of internet influence appears to be the reality of sales and marketing in the recreational scuba world.

And with that it will be interesting to see the type and level of response you get on here.
 
To kick off with the Coltri you need to define the term Heavy Duty

The Coltri MCH 22 and MCH 30 are in effect the same machine just one runs faster the MCH-22 at 1050 RPM and the MCH-30 at 1250 RPM. While interestingly the MCH 36 and MCH 45 simple run even faster with one at 1250 and the other 1420. I leave you all to work out which one its wearing out quicker and already the Coltri term of heavy duty is misleading you from the get go.

Notice also no mention with Coltri of the piston diameters or the piston rod stroke length. Two vital pieces of information with which to make an informed choice. The smaller the piston the faster it has to run the same with the piston stroke the shorter the stroke the faster it has to run. Half the piston stroke you double the RPM Speed and lower the life But you get to sell a smaller compressor block cheaper because its running faster to the PADI folk with a dive shop.
 
rather than the double-acting second stage on an IK12.14. MCH22 also has a much lower RPM.
The Bauer is not strictly a double acting piston but a double acting stepped piston design. Nothing wrong with that.

By comparison some constant duty small high pressure oxygen compressors are single 1 piston stepped triple acting. With two of the stepped rings compressing on the up stroke while the third ring compress on the down stroke. You just need to balance and equalise out the rod loading on the con rod up and down.

Bauer give a little more but essential technical detail as they can IMHO afford to. The IK12.14 is therefore technically a three cylinder four stage compressor block running on a 40mm stroke with the piston set being 105mm/88mm on the double acting stepped piston and 28mm and 12mm for stages 3 and 4.

Bauer also give you the interstage pressures and with this both the pressure and the piston diameter you can work out the rod loading on the bearings with simple schoolboy maths and calculate the low end bearing life expectancy with a little higher maths.

By contrast Coltri give you nothing. No piston diameter and no piston stroke with which to make an engineering informed choice just change the oil more frequently and the evidence of wear is simply flushed away. Ignorance is bliss.
 
To kick off with the Coltri you need to define the term Heavy Duty

The Coltri MCH 22 and MCH 30 are in effect the same machine just one runs faster the MCH-22 at 1050 RPM and the MCH-30 at 1250 RPM. While interestingly the MCH 36 and MCH 45 simple run even faster with one at 1250 and the other 1420. I leave you all to work out which one its wearing out quicker and already the Coltri term of heavy duty is misleading you from the get go.

Notice also no mention with Coltri of the piston diameters or the piston rod stroke length. Two vital pieces of information with which to make an informed choice. The smaller the piston the faster it has to run the same with the piston stroke the shorter the stroke the faster it has to run. Half the piston stroke you double the RPM Speed and lower the life But you get to sell a smaller compressor block cheaper because its running faster to the PADI folk with a dive shop.

@iain/hsm Bauer does have a couple Vertecon models spec'd to run at 1420 so it's not like coltri is the only one. I think a better way to skin this is to point how how important it is for @alanchang to actually compare similar sized blocks because the MCH22 block is much larger than the Bauer block he called out.

Since you called out a specific block from Bauer instead of a specific compressor, if you want to compare like:like then you need to be looking at the Bauer VEC20/VTC20 compressor which is a much more fair comparison. I don't have the block code handy as I'm traveling, but that comparison has the MCH22 moving 550lpm at 1250 rpm vs the Bauer moving 600 at 1300, so that at least says these blocks have similar displacement, now we can compare them.
 
Since you called out a specific block from Bauer instead of a specific compressor, if you want to compare like:like
No look carefully. The OP was quite specific. It is in the title of his post:

Coltri MCH22 vs Bauer IK12.14 Compressor. Which one is better?​

For whatever reason the heading above is what he wants
Its not IMHO as you say a like for like comparison per say.
But a comparison non the less.
 
if you want to compare like:like then you need to be looking at the Bauer VEC20/VTC20 compressor which is a much more fair comparison. I don't have the block code handy as I'm traveling, but that comparison has the MCH22 moving 550lpm at 1250 rpm vs the Bauer moving 600 at 1300, so that at least says these blocks have similar displacement, now we can compare them.
If you want to compare "like for like" the interesting question to me is just how far removed recreational scuba compressors and Nitrox compressors for that matter are from industrial standard certified pure oxygen and elevated oxygen concentration Nitrox compressor standards.

The Coltri MCH-22 pumping 550 LPM at 1250 RPM
The Bauer TBA**** pumping 600 LPM at 1250 RPM
A Certified Nitrox unit pumping 990 LPM at 730 RPM

The only drawback would be that if we continue down this route It may result in affecting the recreational scuba market compressor suppliers position of being a law unto themselves to the ignorant and the ill informed scuba diver. And may affect the scuba dive shop resellers website policy of buy now with the use of a personal credit card choice.
 
No look carefully. The OP was quite specific. It is in the title of his post:

Coltri MCH22 vs Bauer IK12.14 Compressor. Which one is better?​

For whatever reason the heading above is what he wants
Its not IMHO as you say a like for like comparison per say.
But a comparison non the less.
sure, I just wanted to point out that @alanchang is comparing two very different sized blocks. For anyone else watching, the MCH22 is a 120mm x 50mm first stage, ~0.57L, and the IK12 is 105x40 or ~0.35L so we are comparing two wildly different sized blocks. The IK180 is 130x50 and ~0.66L so that is at least a much more similar sized block.

Now, the OP was asking about the differences, and I wanted to point out that he's trying to compare two very different compressors that IMO shouldn't be compared to each other. If you want to compare against the IK12 block then you should really be comparing it to the MCH16 which while only 3-stage and is a bit smaller, is still IMO more comparable than the 22 which really competes against the much larger IK180 pump
 

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