Problem with Coltri MCH6

[happy-diver]

You need to diagnose before ordering and tearing things apart

 

[Wallowa]

True....he is trying to diagnose...any pointers for isolating the issue?

 

[Gone for diving]

From the sound of its isolated to #4 not pumping.

If the relief on the outlet of #3 cylinder is blowing off.... the #4 needs to step it up higher, and if it's not.

Then piston is not moving, or not sealing,
Or check valves are not sealing, or head gasket leaking, if it has one.

That's very basic, but that pretty much covers most of the problems that it could be......

 

[Alex Ouroboros]

True....he is trying to diagnose...any pointers for isolating the issue

From the sound of its isolated to #4 not pumping.

If the relief on the outlet of #3 cylinder is blowing off.... the #4 needs to step it up higher, and if it's not.

Then piston is not moving, or not sealing,
Or check valves are not sealing, or head gasket leaking, if it has one.

That's very basic, but that pretty much covers most of the problems that it could be......

Cheers, this does seem to be the consensus so I’m going to have a look at the weekend,

 

[Alex Ouroboros]

Thanks for everyone,s input I’m having a look at the weekend, as I sort it out I will post an update on here as it may help others.

 

[Alex Ouroboros]

Righto, so Friday just gone I ran the compressor up and using my laser thermometer gun started zapping the barrels and associated pipework to build a picture up of what was happening, and you’ve guessed it, straight up to 245bar with no issues on a twin set (from 200) so I swapped on to another twinset which needed topping up from 100 bar and it got to 120bar before the OPV started popping straight out with the temp gun revealed the 4th stage had already gone on holiday,
So I stopped everything having already resigned myself to a strip down and check the mechanics of the 3rd stage OPV and go from there (I feel much more confident as I’ve had it in a few pieces as I changed the 4th stage only last week) dumped the oil at which point I gave myself a nasty shock as it was black! Black = burnt in my book. So yesterday I did the tear down,
As soon as I removed the plate behind the cooling fan the culprit was evident, a missing circlip on the connector of the 4th stage piston arm had allowed the barrel to work itself halfway out, (quite disappointed in myself here as I thought everything had gone back correctly) after finding and removing the clip and replacing with a new one I then inspected the 3rd stage OPV, nothing wrong there, and reassembled, yesterday evening I took the 120bar twinset to 245, with no problems before topping off a 10ltr, so I think problem solved.

Thanks to everyone for input

 

[Wallowa]

Righto, so Friday just gone I ran the compressor up and using my laser thermometer gun started zapping the barrels and associated pipework to build a picture up of what was happening, and you’ve guessed it, straight up to 245bar with no issues on a twin set (from 200) so I swapped on to another twinset which needed topping up from 100 bar and it got to 120bar before the OPV started popping straight out with the temp gun revealed the 4th stage had already gone on holiday,
So I stopped everything having already resigned myself to a strip down and check the mechanics of the 3rd stage OPV and go from there (I feel much more confident as I’ve had it in a few pieces as I changed the 4th stage only last week) dumped the oil at which point I gave myself a nasty shock as it was black! Black = burnt in my book. So yesterday I did the tear down,
As soon as I removed the plate behind the cooling fan the culprit was evident, a missing circlip on the connector of the 4th stage piston arm had allowed the barrel to work itself halfway out, (quite disappointed in myself here as I thought everything had gone back correctly) after finding and removing the clip and replacing with a new one I then inspected the 3rd stage OPV, nothing wrong there, and reassembled, yesterday evening I took the 120bar twinset to 245, with no problems before topping off a 10ltr, so I think problem solved.

Thanks to everyone for input

Good on you....hey, I was told by Nuvair where I just bought the MCH-6 Icon that I should expect "black/dark" drain oil on the first and possibly second lube change.....I am hyper on early and frequent initial lube changes in new motors/compressors to flush out the residual contaminants left over from assembly and breaking in....suggested first at 5 hours and then for me at 10 hours.

Please keep posting as you get more hours on the beauty!

Suerte...Phil

 

[Alex Ouroboros]

Good on you....hey, I was told by Nuvair where I just bought the MCH-6 Icon that I should expect "black/dark" drain oil on the first and possibly second lube change.....I am hyper on early and frequent initial lube changes in new motors/compressors to flush out the residual contaminants left over from assembly and breaking in....suggested first at 5 hours and then for me at 10 hours.

Please keep posting as you get more hours on the beauty!

Suerte...Phil

In hindsight the blackness of the oil was probably also to do with the new 4th stage running in so I’m not quite feeling as woeful as the other day, and yesterday another twinset went to 245bar, so all good.
Yes will post things as I learn.

 

[Alex Ouroboros]

Ok so this is how things have gone since my last update of my “Coltri relationship”

Compressor sounded in very good health only now it is filling at about 1/3rd of the speed as before, regardless I fill 3 bottles and before they finish filling I’ve already ordered the replacement copper gaskets as I suspect it has gas leakage from the 2nd and 3rd stage heads that I inspected, apart from lost speed at filling cylinders the compressor seems to be good as new,
(ffwd a few days)
Gaskets arrive and by now I’m confident enough just to strip the pipework from the effected areas whip the heads off, have a nosey and replace the gaskets and in the case of 3rd stage the valve in the head also (part of the kit) definitely identical,
I fill 5 bottles all to 240bar feeling very pleased with myself (and back at normal full rate of speed) and then suddenly the 3rd stage OPV pops at 200bar, a little annoyed I think the 4th stage pin and circlip could be the problem again so off comes the crank case cover with the compressor slightly at an angle so I don’t loose oil,, pin, circlip etc are all fine, the oil is black - grey again so I think maybe this is just from the end of the running in, so I run the compressor for 5mins with no load and then replace the oil.
Started filling again and now the compressor only manages 140bar before the OPV that I’m told is set at 200 is popping like a Peterbilt.

I’m going to have a think but I shall post an update when done.

 

[Wallowa]

Damn! Is the OPV intermittently defective/weak? "have a nosey"....love it, totally Brit and I will plagiarize that phrase!

Hang in there....

See if this site helps...https://scubaengineer.com/high_pressure_compressor_filtrat.htm