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Thread: Expobar Minore III - slow pressure loss...

  1. #1
    KJM
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    Expobar Minore III - slow pressure loss...

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    I have a slight issue with the new-to-me Minore III I just purchased from a well known Tamper man ;D - the pressure in the steam boiler (relatively) slowly drops off.

    It isnt a "problem" per se - but it is annoying because I cant figure out where the pressure is going to!

    I have the pressurestat set to 1.2bar and itll be there (say) when I start running a shot and drop back to just under a bar by the time I finish running the shot. Now - I know there is a HX loop in the steam boiler to pre-heat the brew-boiler water. This accounts for a pressure drop. Fine. But there is a steady pressure drop if I do nothing and just watch the pressure gauge... (And presumably if I dont watch the gauge too! ::))

    I initially thought it would be the anti-vac valve suffering a small amount of leakage, but Ive given it a couple of taps with no real result.

    There is no obvious hissing, condensation etc etc.

    Is this normal for the thing? Anyone venture a guess as to where the steam goes?

    Like I said - not an actual problem, but it is annoying me that I cant see where the pressure goes!

    /Kevin

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    TC
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    Re: Expobar Minore III - slow pressure loss...

    Hi Kevin,

    Its a while since I last looked into a minore and I cant accurately recall the hydraulics, but I wonder if it could be a sticky solenoid (per favour of a touch of Adelaide scale) bleeding water destined for the group into the steam boiler instead?* :-?

    Merry Christmas

    Chris

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    KJM
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    Re: Expobar Minore III - slow pressure loss...

    Merry Christmas to you too, Chris!

    Thanks for that idea. Sounds plausible! Ill have a bit of a look after the silly day festivities..

    Just downloaded an exploded parts diagram and I never thought of that! From what it looks like - it seems that water might be able to leak from the steam boiler to the brew boiler inlet.. Which kind-of tallies with slow increase in brew pressure I see with it idle. Ill have some fun sleuthing :-?

    /Kevin

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    Re: Expobar Minore III - slow pressure loss...

    the boiler is pressurestat controlled and so the element will turn on at 0.9bar and switch off at 1.2bar and turn back on again at 0.9bar and so on. Nothing wrong with the machine.

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    Re: Expobar Minore III - slow pressure loss...

    The only reasons that may account for pressure loss during the coffee brew cycle are that the cold water entering the steam boiler HX can cause slight heat loss or a sticky water inlet valve on the steam boiler. Saying this have had a problem similar to this and it was the inlet valve not closing properly and water entering the boiler when the pump engaged. Hope this is helpful
    Cheers Gio

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    KJM
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    Re: Expobar Minore III - slow pressure loss...

    Quote Originally Posted by 7F5B41515A53320 link=1324763366/3#3 date=1324815150
    the boiler is pressurestat controlled and so the element will turn on at 0.9bar and switch off at 1.2bar and turn back on again at 0.9bar and so on. Nothing wrong with the machine
    The steam boiler certainly is, and that works perfectly. My "problem" is that the pressure just slowly falls as I watch. Far too quickly for static cooling of the boiler to explain. Probably something like 0.2 bar in 30 seconds...

    Quote Originally Posted by 46515F1F5557575E5D5C55320 link=1324763366/4#4 date=1324826776
    Saying this have had a problem similar to this and it was the inlet valve not closing properly and water entering the boiler when the pump engaged. Hope this is helpful
    Cheers Gio
    Yup - the more Ive poured over the hydraulic diagram, the more Im convinced that the issue is the solenoid valve that regulates the steam boiler fill. From the hydraulic diagram - it shows the pump going straight to the brew boiler (via the HX in the steam boiler) with a switched Tee to the steam boiler. So whenever the pump runs, it pushes water into the brew boiler and sometimes into the steam boiler. If that valve is a bit dirty - I can see how youd get a slow bleed back to the brew circuit (and the OPV). Having said that, I also see that the solenoid is elsewhere shown with 3 ports... But the nett effect is that there is a single point where both circuits are potentially connected together.

    Anyway, it seems a plausible explanation. I took the E-61 group to bits last night for a clean/lube. Maybe tomorrow Ill drain the whole shebang and take the solenoid valve to bits.

    Thanks for disturbing your Christmas time to think about my problem!

    Cheers
    /Kevin

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    TC
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    Re: Expobar Minore III - slow pressure loss...

    Hi Kevin,

    I have seen this before on machines and I concur that the solenoid is the first place that Id start my investigations.

    Fiddly- but I suspect it will be a relatively routine fix.

    Good luck ;)

    Chris

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    KJM
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    Re: Expobar Minore III - slow pressure loss...

    Quote Originally Posted by 7B4E4344706C4049494A4A2F0 link=1324763366/6#6 date=1324855240
    Fiddly- but I suspect it will be a relatively routine fix.
    So I got bored ::)

    Not so much fiddly as wet! You need to (or rather - you effectively do) drain the boilers.

    The machine has only been used by me on rain water, and by Greg on some kind of bottled water. There was no scale (sorry Chris!)

    What was there was a spherical blob of stuff, which I rapidly identified as one of the resin beads from the filter in the tank!!

    Now I admit I did have the covers off the machine prior to starting this, but it only took 1 hour to do the job. And most of that was me trying to figure out how to drain the boilers without making a mess!

    All fixed!!! No slow pressure drop! Yay!

    (Until the next bit of gunk gets in there... ;))

    Cheers
    /Kevin

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    Re: Expobar Minore III - slow pressure loss...

    Quote Originally Posted by 5051561B0 link=1324763366/7#7 date=1324858565
    What was there was a spherical blob of stuff, which I rapidly identified as one of the resin beads from the filter in the tank!!
    Ahh...man made stuff acting as Scale ;)

    Nice get Kevin and another win for the collective minds of CS. I am glad that all is now well.

    FWIW, I dont have much time for the little resin filters. I have seen severe scale in a machine (Lindas) which receives the best of care and where the softener was soaked in salt water every fortnight as recommended. I think if your water is pre-treated anyway, you may as well bin it.

    Cheers

    Chris

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    Re: Expobar Minore III - slow pressure loss...

    Quote Originally Posted by 6667602D0 link=1324763366/2#2 date=1324773324
    Just downloaded an exploded parts diagram
    Could you share that link as I am having trouble finding one.
    Maybe you or another CSer can help with my small problem though.
    I am wanting to replace the group seal and did not notice the way the old one came out. I am assuming the flat surface goes in upwards with the slightly smaller and rounded edges to the group handle contact.
    On that note of removing the shower screen for cleaning; any easy way apart from prying it out with a lever device?
    Thanks in advance.
    Kevo

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    Re: Expobar Minore III - slow pressure loss...

    Quote Originally Posted by 6667602D0 link=1324763366/2#2 date=1324773324
    Just downloaded an exploded parts diagram
    Could you share that link as I am having trouble finding one.
    Maybe you or another CSer can help with my small problem though.
    I am wanting to replace the group seal and did not notice the way the old one came out. I am assuming the flat surface goes in upwards with the slightly smaller and rounded edges to the group handle contact.
    On that note of removing the shower screen for cleaning; any easy way apart from prying it out with a lever device?
    Thanks in advance.
    Kevo

  12. #12
    KJM
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    Re: Expobar Minore III - slow pressure loss...

    Quote Originally Posted by 7F4A47407468444D4D4E4E2B0 link=1324763366/8#8 date=1324859419
    FWIW, I dont have much time for the little resin filters. I have seen severe scale in a machine (Lindas) which receives the best of care and where the softener was soaked in salt water every fortnight as recommended. I think if your water is pre-treated anyway, you may as well bin it.
    I only have the choice of rainwater or dam water... The rainwater is so soft we have to warn visitors when they have a shower ::)

    You will be pleased to know that as soon as I saw the wee little blighter, the first thing I thought was "right, this aint going to happen again!"... So the machine is basking in its naked water supply now :o

    But now Im running out of coffee things to tinker with, so I might need to either go fishing or slash some grass :-/

    /Kevin

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    KJM
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    Re: Expobar Minore III - slow pressure loss...

    Quote Originally Posted by 133D2E37580 link=1324763366/10#10 date=1324860580
    Could you share that link as I am having trouble finding one.
    Maybe you or another CSer can help with my small problem though.
    I am wanting to replace the group seal and did not notice the way the old one came out. I am assuming the flat surface goes in upwards with the slightly smaller and rounded edges to the group handle contact.
    On that note of removing the shower screen for cleaning; any easy way apart from prying it out with a lever device?

    OK - the diagram came from "disave.com.au"..* Since theyre not a sponsor linkage is somewhat forbidden.* You want the link to the "Office Leva" machine on the Expobar pages.

    The seal?* Thats easy - the cross section of the seal is an upside down U.* The rounded bit goes up, not down!* If the seal doesnt have a "rounded" side, itll have a flat chamfer.* This sits against the showerscreen - the top of which is rounded over.

    Ive never had a problem with levering E61 showerscreens, except when I came back from 6 months long service leave and the Wega in tea room had the shower screen glued on with tarry evil black goo...* I tend to take them off hot (be careful!) and use a stout teaspoon.* There is a tiny groove/dent near the bottom and I put the spoon in that and lever in very small bites.* If I had two teaspoons I reckon youd be able to just ease it down in one go.

    You have to go slowly though, it only moves a couple of mm at a time.

    Cheers
    /Kevin

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    Re: Expobar Minore III - slow pressure loss...

    Quote Originally Posted by 78797E330 link=1324763366/7#7 date=1324858565
    What was there was a spherical blob of stuff, which I rapidly identified as one of the resin beads from the filter in the tank!!
    Hi Kevin,

    I just have bought myself a second hand Minore II. Installed it yesterday and I have the same thing happening! Steam pressure gauge slowly going down to 0.9 bar, red light goes on, back at 1.1 bar and slowly loosing it again. All at idle, the brew pressure gauge is indicating between 1 to 2 bar. Oh, and I have a slow water drip from the discharge pipe too, it seems to go up in the group as my basket has steam / water in it when left on the machine.

    Just to confirm that you found the blob in the solenoid valve?

    Cheers, Ernie

    PS thanks for the link, exploded diagram downloaded.

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    KJM
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    Re: Expobar Minore III - slow pressure loss...

    Quote Originally Posted by 786F7374787A2A2A2A1D0 link=1324763366/13#13 date=1328157732
    Just to confirm that you found the blob in the solenoid valve?
    Yup. Unfortunately for me, I had to repeat the exercise twice. The third time I got wise and had a go at flushing out the boiler >:( Havent had the issue since... The steam boiler seemed to be a reservoir for little filter beads >:( >:( >:(

    The steam boiler will cycle up and down as it cools. On mine the cycle time was probably about 1 minute. It is now >5mins. The heater is on for maybe a couple of seconds to restore the pressure though..

    The discharge pipe? You mean the e61 head or the wee little pipe that annoyingly curves down to the drip tray and catches the cleaning cloth 100% of the time when you wipe the tray?

    If it is the latter - I believe that comes from the pump/opv junction in the hydraulic circuit. So if it drips constantly thatd be an indication of some pressure in there possibly from the steam boiler via the 3-way like I had.

    Somewhat cramped to get at all this stuff, but relatively straight forward.

    /Kevin

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    Re: Expobar Minore III - slow pressure loss...

    Quote Originally Posted by 5C5D5A170 link=1324763366/14#14 date=1328161548
    The discharge pipe?* You mean the e61 head or the wee little pipe
    That would be the e61 head then, with the larger hole, which normally discharges when finishing a shot. It just has a slow but constant drip, when heating up and at idle.

    My timing is similar on the leak of the suspected solenoid, every minute and a half the pressure has dropped and the heating element comes on, it is not a big problem I guess but I dont need to waste energy either and Im more wondering if it could lead to larger problems. Where would a bead travel to further down the lines?

    Bit scary :-/ to pull the thing apart but I have printed the diagram so I might have a go at it. Did you have to replace any seals that I should buy beforehand or are the teflon ones re-usable?

    On the positive side, even whilst still dialling in the coffee grind, dosing, tamping and playing with the temperature I get a couple of noice :) coffees in between the test ones.

    Cheers, Ernie

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    KJM
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    Re: Expobar Minore III - slow pressure loss...

    Quote Originally Posted by 293E2225292B7B7B7B4C0 link=1324763366/15#15 date=1328228708
    That would be the e61 head then, with the larger hole, which normally discharges when finishing a shot. It just has a slow but constant drip, when heating up and at idle.

    My timing is similar on the leak of the suspected solenoid, every minute and a half the pressure has dropped and the heating element comes on, it is not a big problem I guess but I dont need to waste energy either and Im more wondering if it could lead to larger problems. Where would a bead travel to further down the lines?

    Bit scary* to pull the thing apart but I have printed the diagram so I might have a go at it. Did you have to replace any seals that I should buy beforehand or are the teflon ones re-usable?

    On the positive side, even whilst still dialling in the coffee grind, dosing, tamping and playing with the temperature I get a couple of noice* coffees in between the test ones.
    OK - this is easy. (But I have more tools than most 8-)).

    If you dont already have some, grab some food grade high temp lube. I use Molykote 111 (I have a tube of this purchased for something a long while ago. It isnt cheap. A tube will last at least 2x coffee lifetimes..).

    The big teflon washers are 100% reusable. Inside the "seals" are just O-rings.

    You basically need to pull the thing to bits and clean, then re-lube and re-assemble. There are several excellent guides to this on the web. The one in this thread http://coffeesnobs.com.au/YaBB.pl?num=1229912598 has some links to disassembly and reassembly tutorials.

    That thread also has a diagram of the structure of the mechanism - which essentially shows you what the problem must be with your machine. Constant dripping implies leakage from the boiler to the exit - which means the seals in the top half are not happy. This could just be crud or scale even.

    Pulling it to bits is really easy - but youll probably need a large-ish shifter - the actual nut sizes are 22mm, 26mm and 36mm on the Expobar.

    When I did mine, I took it to bits and soaked everything in cafetto. Then reassembled with MK111 and it has been perfect ever since. Took maybe 20mins to tear down, including trips to shed for spannerage; 30mins soaking in cafetto ;D and about 30mins to put it together again. If Id actually read the "servicing e61 heads" links first, it would have been quicker. Nothing quite like wondering which way up a doohicky needs to go... The second time I did this job it took maybe 30min all up to be back in shape again.

    If it still leaks after this, then maybe the seals need replacing. Personally - Id remove them and go to somewhere that sells seals (Consolidated Bearing is convenient for me). Theyll be one or two cents each :o - you can always buy a pile of other O-rings to do the click-on tap fittings or whatever at the same time!

    /Kevin

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    Re: Expobar Minore III - slow pressure loss...

    Thanks for all the links and info. First hesitant* :-/ but then finally bit the bullet over the weekend and dismantled the e61 group head. Found that the top valve housing had a bit of scale build up, also around that o-ring and those viton seals on all three valves were pretty hard. Cleaned it all up, soaked all components in the cafetto and re-assembled it back together. I removed some grease gunk from the mid-valve and decided to use a FDA approved lube that we have to use on our heatsealer -> temperature resistant and food safe grade. At that point I was very happy that it all went back together, no parts left over and the lever moved smoothly. But when heating it up and flushing some water through the next morning, I found that I had gone from the coffee into the drip* ;)* What was a drip just from the bottom was now a constant leak from the shower screen. Almost desperately tried with a backflush hoping to make a a difference to the valves seating and even tried to make a coffee but I had to accept defeat.

    Luckily I had the expoded parts diagram and could quote today straight the part numbers for the replacements, they are literally only costing $0.55 and $0.71 cents each so that was very very reasonable. Cant wait to get them in the mail and pull it apart again, Im sure it will be quicker this time, and hopefully the result will be in the cup* *:)

    Cheers, Ernie

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    KJM
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    Re: Expobar Minore III - slow pressure loss...

    The mechanics of the e61 are pretty straight forward. I actually quite like the overall mechanical-ness of it!

    Be interested to hear how you go when you get the new parts. I assume you did put the springs back in the right order? They are all different!

    /Kevin

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    Re: Expobar Minore III - slow pressure loss...

    Indeed Kevin, since the mechanics go back to 1961, older than me, I figured that it could not be that difficult. With the new viton seals and o-ring the drip has stopped :D

    I found that the heatsealer grease does not last very well, the lever is a bit sticky after a couple of uses and I noticed too that there was a bit of wear on the ends of the valves that ride on the lever cam. So Im going to get some of that molykote stuff and take the handle apart again, Ill probably will be able to do it the third time in 30 min too :P

    However.... without the leaks I have had now a couple of shots with great crema and better taste so it is all worth the effort in search of a cup of gold!

    Cheers, Ernie

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    KJM
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    Re: Expobar Minore III - slow pressure loss...

    Quote Originally Posted by 4255494E4240101010270 link=1324763366/19#19 date=1330513449
    Indeed Kevin, since the mechanics go back to 1961, older than me, I figured that it could not be that difficult. With the new viton seals and o-ring the drip has stopped*
    Hey! - Steady on - I go back before 1961! (Only just though!)

    Quote Originally Posted by 4255494E4240101010270 link=1324763366/19#19 date=1330513449
    So Im going to get some of that molykote stuff and take the handle apart again, Ill probably will be able to do it the third time in 30 min too*
    Yup - it will, but itll also lighten your wallet somewhat :-[ Ive found that I can lube the cam just by unscrewing the lever input cover (to invent a name for the part!) and a skewer applies the lube.

    Ive only had to re-lube after I do a backflush with cafetto. I backflush with water each time I put the machine away. That seems to keep the crud down very nicely. The last time I was particularly bored, I took the cam assembly out and in so far as I could tell there was precious little Molykote left on it. But it was somewhat nicely covered with what I assume are coffee oils. Cafetto removed the oils, but I did try putting boiling water over the thing in a glass first. I couldnt detect any oil coming off it when I tasted the water after. So I suspect the oil in the gubbins of it doesnt actually horrendously modify the taste of your shot.

    Cheers
    /Kevin



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