Results 1 to 10 of 10

Thread: BOEMA rebuild/fix up

  1. #1
    Junior Member
    Join Date
    Aug 2007
    Posts
    9

    BOEMA rebuild/fix up

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    I found this site while trying to find out information about my recently acquired BOEMA 2 group.

    I recently moved from Hawthorn, Melb out to the Burbs (Endeavour Hills). In Hawthorn I went every day for 8 years down to Marios Coffee and Candy, but out here there arent really any options without jumping in the car for 20 minutes. My little Krups machine has stepped up to the challenge well, but still it has that little-machine-home-made taste. I moved for a job in a church and as a bonus they had this machine sitting unused and the person who actually owned it was happy to sell it to me fo $150.

    It was apparently working before the electician cut the aged cord when he test-and-tagged out church equipment.






    Unfortunately it doesnt work and it leaks (probably just need a new seal on the boiler).

    I plan on stripping it and cleaning out the boiler nd other pipes as soon as I figure out what exactly is wrong.

    Symtoms:
    Plug it in a it slowly builds up pressure until it maxes out the guage.
    Turn on the steam and it sprays water until the pressure is gone it 20 seconds (down to nothing).
    When at full pressure it pours well, but the water is only luke warm.

    From playing around inside I suspect its the thermostat that is cutting off power to the element too early.



    The switch opens up when the pressure is up, but the water is still only warm.
    I can see the dial where you can alter the thermostat, but havent been game to start paying yet.

    Before playing with it, is it okay that the pressure is maxed out before the water is hot?

    Thanks in advance for any help.

    If it is just the thermostat that needs adjusting, what tool do I need? I am aware that you are only meant to tighten it to a certain pressure.

    Hamish

  2. #2
    Super Moderator Javaphile's Avatar
    Join Date
    Dec 2004
    Location
    Earth!
    Posts
    15,757

    Re: BOEMA rebuild/fix up

    If it is maxing out the pressure gauge (how high does it go?) and the pressure gauge is accurate but there is very little steam then theres 2 possible causes.

    The first is that theres too much water in the boiler. The boiler should only be filled to about 2/3rds.

    The second possibility is that youre seeing a false pressure as theres either no vacuum relief valve or its not functioning properly.

    First make sure the boiler is filled to the proper level. Then open a steam valve and turn the heater on. Once there is a good stream of steam coming out of the steam wand turn it off. Pressure should then build to somewhere in the range of 1.1-1.4 bar and stabilize there. There should then be plenty of steam available.

    If you start up in this manner and the pressure gauge maxs out something is wrong. Open the steam valve to relieve the pressure and power the machine off until you figure out what the problem is.


    Java "No explosions allowed!" phile

  3. #3
    Junior Member
    Join Date
    Aug 2007
    Posts
    9

    Re: BOEMA rebuild/fix up

    Thanks Javaphile,

    On further investigation I am totally wrong talking about the thermostat. It a pressostat (which is independent of the pressure gauge on the front).

    The pressure gauge maxes out at 400 KPa.

    I am unsure how to test the level of the boiler.

    To be clear, there isnt any steam. It doesnt get that hot. BUT the pressure reads high, which makes no sense in my mind. How is there pressure without the water heating about luke warm?

    so... anyone with a similar machine know how to control the fill of the boiler? or have any idea whats going on?

    Possible newbie mistake: I now have a sneaking suspicion that this is all because there is near to no water in the boiler. Its heating up the air quickly which explains the pressure, but the element isnt actually submerged so thats why there is no heat in the water. Could this be the case?

  4. #4
    Senior Member robusto's Avatar
    Join Date
    Feb 2005
    Posts
    2,782

    Re: BOEMA rebuild/fix up

    Hamish, you should never turn on a kettle or coffee machine without first checking to make sure theres water inside. Otherwise you burn out the element very quickly.

    Its hard to tell from the pics, but located in the middle of the top of the boiler looks like the auto-fil probe.

    (If it is a thin metal probe with an electrical wire attached, chances are it is.)

    With the machine cold, power off, remove the probe and its housing to give access to the boiler. Mark where the probe hits the boiler.

    Then dip a thin skewer or similar to gauge the depth of water. Compare that to the probe depth.

    The elements appear to work otherwise the water would not heat up at all.

    Perhaps the pressurestat is cutting out too early.
    You can adjust it -- usually turning the screw clockwise for lower pressure (less heat) and counter-clockwise for more.

    When you say the gauge maxes out at 400 Kpa -- 4 bar -- is that the maximum possible reading (like a car speedo reads to over 200 kph) or is that the ACTUAL pressure youve been reaching.

    If it is actual pressure, that is very dangerously high. Should be about 100 kpa.

    Has your master switch a position for pump only, and another for both pump and heating?

    -Robusto


  5. #5
    Junior Member
    Join Date
    Aug 2007
    Posts
    9

    Re: BOEMA rebuild/fix up

    I am maxing out the gauge - so yes - its getting dangerously high.

    The pressurestat cuts out at 150 exactly, so thats not the problem.

    I assume the steam come straight from the boiler? If so then the boiler is full, because turning on the steam causes water to come of the nozel, and when I leave the steamer open and pull the water bar on the side it gushes straight out.

    Ill check the levels and get back to you.


    There is no master switch. Its all on at the wall, or nothing at all.

  6. #6
    Junior Member
    Join Date
    Aug 2007
    Posts
    9

    Re: BOEMA rebuild/fix up

    I removed the probe, but it moved a bit when when I removed it so I cant be sure how deep it actually was. Ive now seated in to fill 2/3, and it looks like the same height it was before.


    Same problem. It builds and builds the pressure and the water hasnt got a chance to get hot before the pressostat cuts in.

    I tried something different, and cut off the water supply. Bingo. It now doesnt build up pressure but cuts out soon after the pressostat cuts power to the element, so it sits nicely between 120 and 150 KPa. This makes me think somehow the extra pressure is coming from the mains water pressure.


    So the list of symtoms is now as follows:
    When turned on pressure climbs, even after the pressostat cuts power at 150 KPa (1.5 bar)
    Water not hot but luke warm and no steam.
    Pressure drops to zero in 5 seconds when steam turned on.
    When water turned off at tap the pressure stays nicely in the zone of 120 and 150 KPa (1.2-1.5 bar), water gets hotter, but no steam, and all pressure gone after 5 seconds of steam being turned on.

    Clues?

  7. #7
    Senior Member
    Join Date
    Apr 2007
    Location
    Earth Sth Hemisphere
    Posts
    1,077

    Re: BOEMA rebuild/fix up

    Id be really curious as the the quality of the element, I have a very haphazard approach to these things, pity your not in sydney Id be over in a flash to come help out :)
    all the powdery looking stuff around the welement holes is that from leakage guys? that might point to seal as Hamish suggested...
    Im just shooting at straws here
    Keep us posted with pics, and if you decided to tear it down, get as many photos as you can of each pipe etc different angles, realluy helps if you dont have a manual like mine!
    Im not a sparky but when they test and tag and cut cords there might be a short somewhere? that right sparkys?
    Maybe disconnect power and clean all electrical contacts then test again?
    Id so love to rip that baby apart and take her innards to car lovers
    Good luck dude

    Steve

  8. #8
    Senior Member robusto's Avatar
    Join Date
    Feb 2005
    Posts
    2,782

    Re: BOEMA rebuild/fix up

    Thats somewhat confusing. The pressurestat cuts out at 150Kpa --1.5 bar -- but the pressure then keeps rising, rising, and rising to 400 Kpa --4 bar?

    During that time the pressurestat has not clicked on again, correct?

    That seems impossible. If the pressurestat is off and you can hear it click off, the element cannot keep heating because the contacts are open and no electricity can be delivered to it.

    With the element off, the water cannot keep heating to give a rise in pressure to 400 Kpa.

    So: Are you sure the pressurestat does click off....perhaps the contacts are stuck together?

    Are you correctly reading the pressure gauge: Are there TWO pointers, one for steam pressure (perhaps 50 - 200 range) and the other for brew pressure (up to 1000 Kpa)

    Yes, steam comes out of the boiler. At first it should be wet, after a couple of seconds it should be dry. There is no way you can empty the boiler of steam in just 20 seconds.

    I gravitate to Javaphiles theory that you are getting false pressure --air, not steam.

    Brew water from the groups comes out of a totally different closed circuit, which travels through the boiler which heats that water as it passes through.

    --Robusto




  9. #9
    Junior Member
    Join Date
    Aug 2007
    Posts
    9

    Re: BOEMA rebuild/fix up

    Fixed!

    A dodgy connection on the auto-fill probe causes the boiler to keep filling. Add mains water pressure to a boiler thats trying to heat and it will never get anywhere - the pressostat will cut power to the element almost instantly.

    It was the connector on the top that was worse for wear. wiggle it and it stops trying to fill, but moments later it might lose the connection again. In fact sitting across the room from it I can see the pressure just sky rocketed again.

    Thanks for the trouble shooting help!

    Now to learn about cleaning and stripping.

  10. #10
    Senior Member robusto's Avatar
    Join Date
    Feb 2005
    Posts
    2,782

    Re: BOEMA rebuild/fix up

    Good news Hamish. Sometimes its the simple things we overlook.

    Make sure the other end of the autofill probe --the part that goes in the boiler -- is bright and clean too, otherwise therell be no electrical contact between it and the water.

    Obviously, the pressurestat did its part, but the rising water level squeezed the headroom, increasing the pressure. But since there was so little headroom, so little steam, it depleted in seconds.

    Good luck with the rebuild.

    -Robusto



Similar Threads

  1. BoEma 2 group lever machine (possible rebuild) - madness?
    By nico in forum Brewing Equipment - Extreme Machines ($3000+)
    Replies: 10
    Last Post: 11th April 2013, 11:33 AM
  2. Help with my La Dorio rebuild
    By Racetek in forum Brewing Equipment - Extreme Machines ($3000+)
    Replies: 18
    Last Post: 23rd June 2011, 04:04 PM
  3. 4 Group E61 Rebuild
    By tcm-geelong in forum Brewing Equipment - Extreme Machines ($3000+)
    Replies: 3
    Last Post: 18th May 2011, 07:15 PM
  4. Bezzera BZ-40 rebuild
    By HV_MAN in forum Brewing Equipment (non-machine specific)
    Replies: 41
    Last Post: 9th December 2005, 10:36 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •