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Thread: A Little Help FLuid-O-Tech

  1. #1
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    A Little Help FLuid-O-Tech

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Hi all,
    I just stole a Bezzera BZ35 electronic (or, at least that what is seems to be - no model number but its technicals check as such) at an auction.

    Ive completely gone through the machine, cleaning, replacing seals, etc. and, in fact, it was in rather nice shape to begin with. Everything functions as it should near as I can tell.

    However, I attached a gage to the portafilter (as the machine does not have a pressure gage for either pump or boiler pressure) and Im getting only 3.5bar during dosing. My water inlet pressure is rather high at also 3.5bar so I put a pressure regulator inline to drop it to 2bar as I read somewhere that these pumps are not recommended to run above this.

    So, a couple of questions arise: One, can I trust the gage reading of the Fluid-O-Tech pump with a blocked portafilter? If so, is there an adjustment method for this pump? (I can find no info on this and am not getting a response from Fluid-O-Tech here in the US.) Or should I just go ahead and replace the pump?

    Thanks,
    Docs Coffeebar

  2. #2
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    Re: A Little Help FLuid-O-Tech

    I presume you have a Fluid-o-tech vibe pump in the BZ35e. If so then it is exactly like mine. Low pump pressure could be a result of the diode in the plug connected to the pump being blown (this happened on mine, but didnt result in low brew pressure). Otherwise, can you hear the pump operating? If not, then you problem might be with the relay (simple and cheap to replace). Before that in the chain is the brain box, then the switch panel itself. Its hard to diagnose without seeing the machine and putting a multimeter across it. If the pump is trying to run, then the brain-box/switch panel should be fine. The OPV setting might also be incorrect, of the OPV not functioning properly. This is a simple mechanism consisting of a slotted screw (white plastic adjustment), spring, ball and seat. If the ball isnt seating properly, then the OPV will be stuck on and bypass the pump giving you line pressure only.

    There are plenty of options to explore. You have to try and systematically reduce these.

    Feel free to ask more questions if you have some specifics.

    Regards,

    Mark.

  3. #3
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    Re: A Little Help FLuid-O-Tech

    Thanks for the input Sparky. It is a fluid-o-tech vibe on a BZ35. The pump is trying to operate, that is, it is a getting a signal and I see pressure build on the portafilter gage after iniating a shot- just not much. I think I hear it operate at times such as immediately after turning the machine on and immediately after initiating a shot. It is not a continuous sound.

    I have made small adjustments to the OPV, say, one turn CW, one turn CCW without any effect. Not having prior experience with these, Im a bit cautious about making large adjustments. I hadnt thought about the OPV being stuck, certainly a possibility. Is it possible to disassemble this without destroying it or otherwise ending up with a mess on your hands or is it better to simply crank the adjustment all the way in or out? What do you think?

    I also considered that supply volume could be a problem because I am using 1/4" supply line connected to the main 3/8" line but it seems to me that volume shouldnt be an issue if Im dead-heading to the portafiliter (when the gage is attached).

    A couple of other things I can think of to try: One is to temporarily block the bypass valve and see if the pump will build pressure beyond what Ive already seen. That should tell me whether or not the pump itself is okay or there is an issue with the OPV. Do you see any issues in doing that?

    To test supply volume and pressure, Ill simply drop the main 3/8" supply hose into a bucket of water and let the machine pull from there. That should eliminate these factors as a concern.

    Ill check the diode though this is most probably in there only to protect the brain from back supply when the pump shuts off and therefore shouldnt have any effect on the pump operation.

    Anything else you can think of that I may have missed?

    Thanks,
    Docs Coffeebar

  4. #4
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    Re: A Little Help FLuid-O-Tech

    Last first. The diode is not just there to protect against a back-emf, but to act as a half-wave rectifier. Vibe pumps use only half an AC cycle to energise the electromagent and drive the piston. The other half is a relaxation phase where the internal spring drives the piston in the opposite direction. If the diode fails open circuit, the pump wont run at all. If it fails closed circuit (my case), the pump will sound strange, very loud, but not pump efficiently. The diode is located in the plug and is easy to check with a multimeter. A replacement is simple enough as well. I scrounged a properly rated diode from an old computer monitor.

    If the OPV is faulty, then blocking the bypass should cure it. There is another safety pressure relief valve in the system, so overriding the OPV on the pump should be fine.

    If the pump is faulty, but still runs, it will be harder to diagnose, but a pressure portafilter should be a good indication. These pumps are reasonably cheap and easily replaced. Much cheaper than rotary pumps. (about AUD$70).

    It sounds like your pump is running. For instance does it run continuously when you push the middle brew button? The pump could also be turned on by running some hot water from the tap until the autofill sensor triggers.

    I run my pumps from reservoirs and I find that sometimes they need to be re-primed if some air hasd gotten into the system. This is simply done by pressing the brew button until water flows freely from the group.

    As for the OPV, it is not too sensitive and is a very simple device, just a plastic screw (with an o-ring seal) spring and ball. You can easily pull it apart and check for wear. Its easy to put back together, just put the parts back in the correct order ;-)

    It sounds like you have a few ideas to check.

    Goodluck. These are great machines when running properly.

    regards,

    Mark.

  5. #5
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    Re: A Little Help FLuid-O-Tech

    Hi Docs
    Where are you located ?

    Its handly to have this info in your profile.

    Craig A

  6. #6
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    Re: A Little Help FLuid-O-Tech

    Okay a bit more info.

    Sparky, right, the diode would act as half wave rectifier - this is AC afterall. Anyway, the diode checks okay. So I disassembled the pump. I expected a bit more than ... a spring??!!! Thats it??!!!

    After recovering from my initial amazement at not being peppered with all manner of little widgets flying out from some seemingly random arrangement making reassembly a near impossibility, I reminded myself this is an oscillating pump and therefore only needs some component to move forward and back. I wont tell you a discovered or even understand what that component is but I reached a level of acceptance with the simplicity of the mechanism that allowed me to continue uninhibited by my ignorance.

    There was corrosion on the two halves of the pump (if youve had one apart, you know what I mean) which tells me that at some point the pump leaked intenally. I dont find this a bit surprising and, frankly, I dont know why the thing doesnt continually dribble onto the countertop below as I couldnt find any seals inside!

    I cleaned it up until the halves slid together freely presuming they were meant to do so. I did not break the halves down further as I dont have a drawing or diagram and there are no obvious signs of the assembly method such as threads, spanner flats, hex bolts etc. Generally, I rule out sawing, slicing, beating et. al. as reversible disassembly methods.

    I reassembled and installed the pump and ran a shot. The pump now operated smoothly and quietly, a nice barely audible hum, and built pressure - still only to about 5.5bar.

    Looking at the plumbing it occurs to me that the OPV is nothing more an adjustable check valve that feeds the pump output back to the pump inlet when pressure is above the setpoiint. Armed with this irrefutable logic (Im reminded from History lessons that wars have been started with less clarity of thought) *I proceeded to crank the OPV adjustment first inward to stop and then outward until I get wet (heh, heh, cute) while observing the gage on the portafilter for *change. Nada. Zip. Zilch.

    So, for my efforts, I remain ignorant, or at a minimum, unenlightened. (sigh) I still dont know if the problem is the pump, the OPV, or (horrors) the gage. (Okay, Im ruling out the gage, first because I paid at least 4 bucks for it but mainly because I dont need a third variable - hows that for scientific?) Im also going to rule out the OPV because if it is stuck, why would it be stuck at a point other than near the optimum setpoint, especially why would it be stuck above the setpoint? If anything, it should be stuck closed. (Like that argument? I should have been a lawyer. Oh, wait a sec...Im in the US. Maybe I am a lawyer.)

    Ill disassemble the OPV if for no other reason than it is there (kind of like climbing Everest) but Im thinking pump - unless yall (Texas contraction) have other ideas.

    The good news is Coffee Parts has a 110v 60hz pump in stock.

    Cheers,
    Doc

  7. #7
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    Re: A Little Help FLuid-O-Tech


    Hi Doc,

    If the gauge is broken than you should be able to make a decent espresso with the machine. Otherwise, if the pump is broken and youre running off a tank, youll have trouble getting any water through the coffee. If the OPV is stuck open, youll have to bypass it to test the pump.

    Yeah pumps arent too expensive, and that seems to be the worst case scenario for you.

    Dont worry mate, youll get it running again, and once its running youll find its a good machine. Definitely one of the simpler HX machines to learn out there, but more than capable of producing exquisite results.

    Cheers,

    Mark.

  8. #8
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    Re: A Little Help FLuid-O-Tech

    Okay, a quick update (and a lesson or two learned).

    Never discount anything - including the capability of a brand new gauge. Yep, problem #1 - the brand new gauge I had connected to the portafilter is faulty. I connected it directly to my supply and got the same reading as when pulling a shot on the machine - 5.5bar. Ignoring for the moment that I live on the 22nd floor where it is extremely unlikely that I am getting anywhere near 5.5bar, I also have a pressure regulator in the line that is fixed at 2bar. So, ba-a-a-d gauge (go to your room!)

    And of course the other useful bit of information from this little exercise is that the pump is not working at all as evidenced by my line pressure and shot pressure being equal. So, the little bugger hums but otherwise does nothing to boost the signal as it were.

    So, now that I am conclusively replacing the pump I am fighting the temptation to try to shoehorn a rotary vane pump into the machine. Anybody every try that stunt? Think the relay can handle a bit more wattage required for a real motor? Or would this be useless hot-rodding given the boiler size? And, then, why I am even doing this when Ive got a perfectly good LaPavoni 2-group sitting right next to this little machine? (One wonders.)

    And, Sparky, what is an "HX"?

    Doc

  9. #9
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    Re: A Little Help FLuid-O-Tech

    Hi Doc,
    just some experiences i had for the past weeks on pumps and valves. Hope its useful.
    My Wega/Astoria CKX stopped pumping out any water and the Fluid-o-tech pump just hummed instead of the louder pumping noises. To cut the story short, my tech support got me to replaced my pump, which didnt solve anything.
    In the end it was the by-pass valve that was jammed. The blue plastic piece was jammed together with the spring coil. Solved by pushing everything back in place with a TOOHPICK!
    My guess on why it jammed was due to the high inlet pressure when i tried to plumb it in to the mains.
    Well for all the effort and espresso-deprived months, at least now i have a working machine and a spare pump ... *;)

    Good Luck!
    kai seng

  10. #10
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    Re: A Little Help FLuid-O-Tech

    Behmor Brazen - $249 - Free Freight
    HX = heat exchanger. Sorry for shameless acronym usage.

    The BZ35 can actually ship with a rotary pump, so there is no problem fitting one if you can do it. But is it really necessary for a 2.0l boiler single group machine? The fluid-o-tech pumps are nice if they work properly. Im still having issues with mine. I got a replacement pump with the machine but have used it in my Faema project. I might get another pump and see it it cures some lingering questions about how my machine performs.

    Cheers,

    Mark.



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