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Thread: La Cimbali Junior Rebuild Advice

  1. #1
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    La Cimbali Junior Rebuild Advice

    I recently acquired a La Cimbali Junior of unknown age or condition, that has been in storage for 6 years after being removed from a chicken shop.
    Quite frankly I wasn't expecting much and first impressions did not change that expectation. It was filthy and very sticky.
    On opening it up it turned out to be a Junior D/1 (no external labels whatsoever) - plumbed model with vibe pump and dosing chamber. I still don't know it's age other than "old".
    The filth continued internally with much dust and grot sticking to all surfaces with, what I can only guess is, a layer of chicken fat.
    However to my surprise there is minimal rust, and even more surprising, almost no corrosion visible around any of the plumbing joints.

    The sight glass showed that the boiler is half full and I manually topped up the dosing chamber.
    I tried my luck and plugged it in. No Bang! It didn't trip the earth leakage. Tick.
    I heard a relay click but no front lights turned on. I assumed nothing was happening.
    I waited and after approximately 2 minutes I heard distinct sounds of water starting to boil.
    Heater element works. Tick.
    But nothing visible yet on the boiler pressure guage. I switched it off.

    My question is: can I continue letting it heat? Is it safe to do so? What if the guage is defunct and the safety pressure valve fails?

    What I would really like to do is find out whether the boiler leaks / is cracked before completely stripping the machine down to it's components and cleaning, descaling, acid washing etc.
    Am happy to replace solenoids, pstat, but repairing a damaged boiler is beyond me.

    Will post some pictures when I get a chance.
    FYI - I am coming from a Single Boiler (rebuild) background so the whole HX (rebuild) experience is quite new.
    Thanks.

  2. #2
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    Not familiar with this machine, but googling reveals a pic or 2 to give me some ideas.
    Open steam valve and pump some pressure backwards up the steam line. I have made a fitting from a car tyre valve and a bit of tubing. I connect to a bike pump with a gauge. Pump it up in stages to 20psi (1.5bar ish), check for leaks as pressure raises. You can even shut steam valve and check it holds pressure over time or look for leaks with bubbly water. You can then increase pressure some more to check safety valve operation. You will need to check what pressure it should vent at.
    So you can now find/fix leaks in the boiler circuit with a cold machine.

    Then plug it in and let it heat up knowing that it is ok. Check brew path with pressure gauge, check pump free flow figures.
    Fat and grease is easy to remove with caustic. Try looking at labels on bbq cleaner and oven cleaner. Careful it will eat aluminium.
    Report back.
    saeco_user likes this.

  3. #3
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    Quote Originally Posted by saeco_user View Post
    I waited and after approximately 2 minutes I heard distinct sounds of water starting to boil.
    Heater element works. Tick.
    But nothing visible yet on the boiler pressure guage. I switched it off.

    My question is: can I continue letting it heat? Is it safe to do so? What if the guage is defunct and the safety pressure valve fails?
    It sounds like it is working just fine - you will hear sounds of water moving in the boiler after a couple of minutes as the water touching the element heats and rises to the top of the water level.
    The boiler gauge won't register straight away, as the water has to heat above 100 degrees C before any steam pressure can be generated. If you are worried about letting it heat further, then leave the steam tap open until steam starts coming out, then close it - you should see the boiler pressure gauge start to register some pressure. The pressurestat should be set to 1.5 bar or less and the safety valve should be rated to something like 2.5 bar, so as long as you watch the boiler gauge and turn the machine off if it looks like it is going to heat past 2 bar, there is zero risk of anything catastrophic happening.
    saeco_user and Jackster like this.

  4. #4
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    Does the pump turn on when you hit the brew switch.

  5. #5
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    Thanks Morgan and Jackster both good ideas.
    I turned it back on and left the steam tap open. Pressure built up just fine, got to just over 1 bar, pressure stat clicked in.
    Pressure guage working. Tick.
    Pstat working. Tick.
    No leaks from boiler. Tick.
    Antivac valve continuously hissing. No surprise really and no big deal. Will fix or replace.
    Lots of relay activity when heating.
    Dosing chamber full of water but level probes may be corroded and not sensing level, causing the doser to try and refill.
    Boiler sight glass shows half full but may be same problem with boiler level probe.

    Quote Originally Posted by Greenlai View Post
    Does the pump turn on when you hit the brew switch.
    Hit the brew switch, water dribbled out the group but pump did not turn on.
    Have not yet connected to mains water supply. Not sure if this has any bearing as pump pulls directly from dosing chamber.
    Possibly if boiler level sensor is reading low, pump will not turn on, but would not have thought the group solenoid would open, which it does.

    May try connecting to mains next and see if this helps identify which solenoids the relays are turning on and whether it has any bearing on pump operation.

    Thanks for your input.

  6. #6
    Senior Member artman's Avatar
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    Leaking anti vac easily fixed by replacing o ring for a few cents or entire vlave for a few $.

    Might have a sticky solenoid if its dribbling but if pump did not turn on then you wont be getting any flow.

    Have you tried isolating pump to see if it is working? the pistons can seize, easy to pull apart and check/clean or new pump is not that pricey if it is dead.

    Cheers

  7. #7
    Super Moderator Javaphile's Avatar
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    Once the machine has warmed up have you turned the power switch to it's 3rd position?


    Java "Had to ask" phile
    Toys! I must have new toys!!!

  8. #8
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    Quote Originally Posted by Javaphile View Post
    Once the machine has warmed up have you turned the power switch to it's 3rd position?
    Java "Had to ask" phile
    Mine doesn't have a third position.

  9. #9
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    Quote Originally Posted by artman View Post
    Have you tried isolating pump to see if it is working? the pistons can seize, easy to pull apart and check/clean or new pump is not that pricey if it is dead.Cheers
    Not yet, but will do. It is a "lunchtime at work" type project - I haven't been game to bring the beast home yet - and things happen very slowly.

  10. #10
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    Quote Originally Posted by saeco_user View Post
    Hit the brew switch, water dribbled out the group but pump did not turn on.
    Have not yet connected to mains water supply. Not sure if this has any bearing as pump pulls directly from dosing chamber.
    Possibly if boiler level sensor is reading low, pump will not turn on, but would not have thought the group solenoid would open, which it does.

    May try connecting to mains next and see if this helps identify which solenoids the relays are turning on and whether it has any bearing on pump operation.

    Thanks for your input.
    Hitting the brew switch should start the pump for brew water through the HX irrespective of boiler water level. If there is no noise from the pump then the problem is either your switch or your pump. If the pump kicks in but there's no water then a common problem is a vapour lock solved by priming the pump by connecting it to the mains water or forcing/injecting water into the pump while its on.

  11. #11
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    Quote Originally Posted by Greenlai View Post
    Hitting the brew switch should start the pump for brew water through the HX irrespective of boiler water level. If there is no noise from the pump then the problem is either your switch or your pump. If the pump kicks in but there's no water then a common problem is a vapour lock solved by priming the pump by connecting it to the mains water or forcing/injecting water into the pump while its on.
    Thanks Greenlai. No, pump does not kick in at all. Will pull it out later.
    Last edited by saeco_user; 1 Day Ago at 11:47 AM. Reason: typo

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