1987 Bauer Capitano - Questions

[Bloody Knuckles]

I recently acquired a 1987 Bauer Capitano off of Craigslist. I believe the unit was originally equipped with a gas engine and converted to electric. The motor currently being utilized is a 3 HP Baldor and it came with a control box (see attached). Subject to the sheave sizes (5" and 18"), I figure it should be operating around 950 RPM (plate on motor says 3450 RPM).

The compressor turns over freely by hand. I drained the oil and inspected for water / contaminates (all good). I replaced the oil to run it for evaluation.

Unit seems to run fine, oil visible in sight glass (no bubbles). It seemed to pump air ok beyond the PMV (no gauge attached yet, so I'm figuring it's pumping around 2,000 PSI if the PMV is working ???).

I ran the unit for about 5 minutes, bleeds worked fine with the typical water / oily mist discharge.

My concerns... The first and second stage warmed up to the touch as expected but the third stage was cool. Is this a possible stuck "floating piston"...I'm really not sure how that system works. Again, it sounded fine...No excessive knocking or rattling. (I'm not sure how it could pump air past the PMV if the piston wasn't working, but why so cool?)

Upon shutdown I could hear air bleeding out the intake. I removed the first stage head, cleaned and inspected the valve components (only minor carbon build up easily removed with a light scrubbing). The cylinder and piston dome looked nice and clean. I re-assembled and ran again...No change.

Before I progress further, I was looking for some thoughts and or direction.

Regarding the PO purification system...Yes, I know it needs to be changed and it will be if I'm not dealing with a hot mess...Baby steps

FWIW, I have little to no experience with the Bauer line. I do own a Coltri MCH-6. (Yes, I know it's a P.O.S. rattle trap, no desire to get into that debate). All's I can say it has treated me well. That being said, the Bauer unit seems to be very rugged and well engineered with any luck I can increase my knowledge base to n=2.

 

[Tracy]

I don't see a PMV in your pictures.
Start with a valve and a gauge, see what it is doing first. Troubleshooting problems that you don't know exist will get frustrating quickly.

 

[oldairdude]

Michael,
Without a gauge, it is difficult to determine much about some of these issues. Let me ask you, did you hear a loud "knocking" of the floating piston on startup? If so, safe to say that your final piston is free. Did you have to wait about 30 or so seconds before air discharged out the filter? If so, you have something of a PMV in play. By the way, your PMV is located at the very bottom right corner of the P-0 filter housing (where the hose would hook-up) Remember that with your 3 HP motor you are only producing about 3 CFM. It may take awhile for it to stop the knocking sound and produce enough back pressure to not only stop the knocking, but also open the PMV and have air discharge. If it starts blowing air out as soon as you start it, your PMV is faulty and you have no real pressure. (unless you add a hose and gauge and valve...)
By the way, the second stage is the warmest stage on that unit, I would not be too worried yet about the coolness of your final stage at this point. You need to run it for 20 to 30 minutes with a known load of at least 2000 PSI to determine if you even have an issue there.
As for the "air leaking" at shutdown, this is normal without an auto-drain feature. Air will leak from all three stages into the crankcase while running and even more on immediate shutdown. Once its in the crankcase, it is routed back to the 1st stage head, via that nylon tube going in your 1st stage head. When you get even hotter by running it longer, you may also see a little oil vapor (smoke like) coming out of your intake housing as well. All normal.
If however, it drains your full filter backwards into the compressor block, (like hearing it continue to leak even though you drained the second stage drain) then you most likely have a final stage discharge valve that needs to be examined or replaced. But you are not there yet...

 

[Bloody Knuckles]

I don't see a PMV in your pictures.
Start with a valve and a gauge, see what it is doing first. Troubleshooting problems that you don't know exist will get frustrating quickly.

The PMV is integral to the P0 Purification Filter Housing (see lower right in photo). Unfortunately all my hoses and fittings are JIC-4. The fill hose and fittings provided with the Bauer are larger (#5 or #6...not sure yet?) Anyway, a bit of a cart / horse issue. Yes, once I can get the fittings I'll proceed as your suggesting. Am I chasing my tail with air venting out the intake after shutdown...IDK, my Coltri holds the pressure, I would assume the Bauer would also? Frustrated...Hell no, just having fun

 

[oldairdude]

Correct, get a hose to evaluate before you go crazy. The Bauer unit has far more internal space with pressure, like larger intercoolers, cylinders, etc. to be able to hear it leak. The little Coltri only needs to fart and its over. I can not tell with these photos but if you have an adaptor attached to the PMV. you may be able to change the output fitting by simply adding a male JIC adaptor. (Important! the threads on the PMV are 1/4BSPP...not 1/4 NPT!! only an adaptor should be threaded in there)

 

[Bloody Knuckles]

Michael,
Without a gauge, it is difficult to determine much about some of these issues. Let me ask you, did you hear a loud "knocking" of the floating piston on startup? If so, safe to say that your final piston is free. Did you have to wait about 30 or so seconds before air discharged out the filter? If so, you have something of a PMV in play. By the way, your PMV is located at the very bottom right corner of the P-0 filter housing (where the hose would hook-up) Remember that with your 3 HP motor you are only producing about 3 CFM. It may take awhile for it to stop the knocking sound and produce enough back pressure to not only stop the knocking, but also open the PMV and have air discharge. If it starts blowing air out as soon as you start it, your PMV is faulty and you have no real pressure. (unless you add a hose and gauge and valve...)
By the way, the second stage is the warmest stage on that unit, I would not be too worried yet about the coolness of your final stage at this point. You need to run it for 20 to 30 minutes with a known load of at least 2000 PSI to determine if you even have an issue there.
As for the "air leaking" at shutdown, this is normal without an auto-drain feature. Air will leak from all three stages into the crankcase while running and even more on immediate shutdown. Once its in the crankcase, it is routed back to the 1st stage head, via that nylon tube going in your 1st stage head. When you get even hotter by running it longer, you may also see a little oil vapor (smoke like) coming out of your intake housing as well. All normal.
If however, it drains your full filter backwards into the compressor block, (like hearing it continue to leak even though you drained the second stage drain) then you most likely have a final stage discharge valve that needs to be examined or replaced. But you are not there yet...

Yes, it did nock a bit initially but quieted right down, so I guess that's good. Yes, there was a delay until discharge from the PMV (I'll give it another whirl and pay more attention to the time). Regarding the utilization of a 3 HP motor and subsequent reduced RPM (approx 950 RPM at the flywheel) is that cause for concern or does it result in just a reduced about and slower fill rate? I'll check again to see if the P-0 filter housing is draining...But I think it did.

 

[oldairdude]

Michael, it only effects the charge rate, and with that, perhaps a bit longer to overcome the PMV setting before any significant air escapes out. Some small leakage is normal until it fully opens. You will hear it when it does. On the plus, your unit should run cooler at the reduced speed. It allows for more dwell time in the intercoolers as well.

 

[oldairdude]

By all accounts of your description above, it seems to be doing everything it should. That's a good sign and a good start. The P-0 is manual drain only on that unit. Once you have a hose or filling a tank, you can test the quality of your final discharge valve by simply leaving a tank open to the line after turning off, and if you hear the air constantly leaking for minutes, then your discharge valve needs attention. Easy fix...
Unfortunately the P-0 does not have an internal check valve per se, however I do recommend that you add one at the discharge of the PMV where you hookup your hose.

 

[Bloody Knuckles]

By all accounts of your description above, it seems to be doing everything it should. That's a good sign and a good start. The P-0 is manual drain only on that unit. Once you have a hose or filling a tank, you can test the quality of your final discharge valve by simply leaving a tank open to the line after turning off, and if you hear the air constantly leaking for minutes, then your discharge valve needs attention. Easy fix...
Unfortunately the P-0 does not have an internal check valve per se, however I do recommend that you add one at the discharge of the PMV where you hookup your hose.

Well, had some more fun after work... Based on Porters comments, I ran the compressor again trying to determine if the PMV was working (this is all in the name of science because it's getting replaced anyway along with the entire P-0 purification system). I put the discharge hose in a bottle of water to observe the amount of air being generated and when. Unfortunately it started blowing bubbles right away and in my opinion not a whole lot of volume. It also continued to bleed air out the intake when shut down. My curiosity got the best of me and again based on Porter's comments, I pulled the third stage head to investigate. From my limited experience (which is none), I would say the discharge valve is probably toast and the floating piston was stuck pretty good (see attached). So, my questions...Porter do you have any valve kits in stock and what are your thoughts on the floating piston...Should it slide completely out of the cylinder? At the moment I can move it about an inch or so in either direction before it starts to bind up. It's currently sitting in a bath of penetrating oil...Hopefully that will help. Regarding the intake valve, it seemed to pass the "suck and blow test" but I'm assuming it should be replaced as a set which leads me to my next question. Do I need the "special" tool or do you have a trick for that?

 

[oldairdude]

OK, it may not be as bad as you might think. The valves could have been a bit loose or it was time to replace. Either way a simple fix, and yes you will need the valve tool to remove and replace the final stage intake valve. Its about $40, no big deal and will be needed for the second stage as well. I have plenty.
After soaking this piston, do not force it to come out, this may do more damage than good. Instead oil the piston and bore with compressor oil the best you can for now, and reinstall. Just don't force the issue, as it may gall. There is a lot of carbon on the valves, perhaps from using petroleum oils or overheating...
Since it did not fully seize from running earlier, you might be out of the woods. You had no bubbles earlier also so that's a positive. I would try this one again first. Perhaps a new one is in your future, wait and see.
The valves most likely need to be changed out, but for now clean and reinstall so you can try to move forward. (plus you do not have the tool to replace yet) I'll contact you about proper tensioning of the discharge valve. Read that manual on that subject.
On the PMV leaking out, as I said, some air will come out right away on a worn one. Not 3 CFM, but some. Don't worry about that now...