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Thread: La Cimbali Junior R

  1. #1
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    La Cimbali Junior R

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Hello all

    Having seen but missed out on Sparkys recent BZ35E sale, I had decided that I just had to have an HX machine. But given funds, it had to be second hand - I figured I would be waiting awhile.

    But lo, up popped an ad in the Quokka a week or so ago (our local Trading Post here in WA) for a single group coffee machine for $300. On enquiry, the guy didnt know much about it - he thought it might be called Ciambli - but could tell me it was big - 50cm by 60cm at the base. I got excited.

    On turning up for inspection, it turns out it was indeed a La Cimbali Junior. But an older semi-automatic Typo R.

    The outside didnt look toooo bad. I pulled the side off the machine to look inside, and was appalled.

    However, the vibe pump was working and the boiler heated water. As the guy was prepared to accept $200, I pinned my ears back, and bought it. I figured the value of the stainless steel and copper as scrap would be worth almost half this price.

    On return home, I went to show the missus, and tripped the fuse in the house. Turns out the drive home had seen the end of the heating element ($85 at coffeeparts and counting, kerching).

    Other bad points are: the extent of rust; the state of wiring; the worrying calcinous growths on the boiler around some of the flanges; and the cockroach inhabitants.

    Good points are that the vibe pump works (well goes, lets put it that way); that the rust is mostly superficial; the electrical controls under the driptray are in quite good nick (no water has found its way in here obviously) and that its a Junior (built like a tank, mainly out of stainless steel).

    See attached piccies.

    Anyway CSers, what do you think? Should I cut and run now, and save my money? Or is it redeemable? Comments appreciated!

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    Re: La Cimbali Junior R

    BTW- some piccies follow (kindly resized by Coffee kid)

    (maybe you could PM me Coffee kid to tell me how to stop the oversize piccy problem)

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    Re: La Cimbali Junior R

    Resized it :)


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    Re: La Cimbali Junior R

    and second


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    Re: La Cimbali Junior R

    The outside of your Chumbly looks OK but I cant say the inside looks as inviting.

    The experts should be along soon to appraise your new toy.

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    Re: La Cimbali Junior R

    Off topic replies have been moved to [link=http://coffeesnobs.com.au/YaBB.pl?num=1175002782]This Thread[/link]

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    Re: La Cimbali Junior R

    Good one Dennis. I like the extra heavy-duty thermocouple on the boiler --looks like your boiler is also designed to radiate excess heat to the air. ;D ;D

    Slowdown, agree with TG, the inside looks a mess but outside its quite presentable. But whatever the situation, you are starting from a base of $200 and its a matter whether your budget also happens to coincides with the cost of work that needs to be done.

    It looks as though thereve been many leaks, which have already done their rust damage but should be easy to remedy with a spanner and the odd seal.

    If you have the patience and inclination, youd want to strip it all, taking photos and labling as you go, and thoroughly clean every piece in citric acid, and pay attention to the frame.

    But Ill leave all that to the experts here to advise you on.

    Good luck,

    --Robusto

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    Re: La Cimbali Junior R

    For $200 you got a bargain. The best person to talk to about the restoration here is mauricem, who has two LC Juniors and has carefully restored them. The thread is on here somewhere if you search. But for peace of mind, youll have to completely strip it down and restore it piece by piece. For a machie this size, its not such a big drama and youll learn about how the machine works in the process.

    Id probably look at getting a new pressurestat as well, as the cover seems to be missing from the one you have. These Sirai units are pretty industrial, but that still looks pretty beaten up.

    Id expect all up a restoration will cost less that $500-600. Seals are pretty cheap and most of the metal probably only needs a clean/descale. The one thing you dont want is a leaking boiler. They can be repaired, but the cost will skyrocket. Some older Cimbalis use a stainless steel boiler, *and this can be a problem, as stainless steel is generally not too stainless at steam boiler temperatures, and can corrode. This is a problem with old La Marzocco machines and has been reported with even new Synessos if the chloride content of the water is too high.

    All in all, fingers crossed, you have an potentially awesome machine. Once its restored it should run for years and La Cimbalis have a reputation for producing great shots once you learn to drive them.

    Good luck with the restoration and keep us posted.

    Cheers,

    Mark.

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    Re: La Cimbali Junior R

    Thanks for your heartening comments Mark - my better half will be relieved.

    Certainly being elevated to the hallowed heights of an extreme machine - $3000+ puts it all in perspective

    Thanks for the tip re mauricem - I found threads on HB and alt.coffee where he in turn was tic tacking with Ken Fox who seems to be a bit of Junior guru as well. So plenty of material there.

    Youre right about the boiler - I am worried it has a leak around the HX neck where it joins on the boiler. I think I may have to have it welded/brass soldered here. On this point, I thought the boiler was stainless steel but I have discovered a spot where what seems to be chrome has chipped off exposing copper coloured material underneath. With a bit of luck, given your comments, it is indeed a copper boiler after all.

    I am slowly stripping down for a full rebuild. I pulled the element out of the boiler and was pleased to see that there wasnt too much scale at all in there - which augers well for the grouphead. I will follow your technique on your BZ thread (I recall something about citric acid, phosphoric acid and even a caustic just to finish things off - but I forget the details as I dont have that thread in front of me right now).

    Ill also put a new Sirai PS in - they are less than $100 - and the existing one is shagged (on to its last of three relays).

    Overall, I am hoping that I will get away for less than $1000 - which was my budget.

    PS Dennis - sorry your $100 CX500 got booted to off topic - tch tch. But hey, this project will give me as much pleasure as restoring my AJS500! Know exactly where youre coming from. Cheers

  10. #10
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    Re: La Cimbali Junior R

    What a great pickup!
    No doubt youre already aware that all the spares you need can be got from Pedro at Coffeeparts.
    Not a bad saving over a new one at about 4 grand.

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    Re: La Cimbali Junior R


    Regarding the boiler: Nickel coated copper is common in a lot of machines and is good to have. I believe mauricem tested his boiler material and found it to be nickel plated copper as well. Beware that copper is relatively soft, so too much force/torque on fittings can cause the boiler itself to warp or distort and can cause some joints to crack. So be careful. To loosen the fittings use either an impact wrench, or a hammer to tap the spanner to first loosen the fittings. Also be careful not to over tighten the compression fittings. They dont need to be too tight to work. For example I believe Swagelok state that you hand tighten the nut on the fitting and then tighten further 1/4 of a turn. That sounds about right to me.

    If youve read all those threads, then you know what sort of machine you have. Its worth going to the trouble to restore fully.

    Cheers,

    Mark.

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    Re: La Cimbali Junior R

    Slowdown,

    A belated welcome to the La Cimbali owners club.... (Ive been busy on other "projects")

    They are indeed great coffee machines and although the interior looks a bit scruffy, I think you will find with a bit of patience and elbow grease it will come up a treat. A lot of the gunk inside most commercial machines is coffee grounds, coffee oils and assorted yuck!!! The exterior is kept clean but the interior - well thats left to its own devices.

    They are very solid units and it sounds like your boiler etc is in particularly good nick, so Id do a strip and rebuild and you will have a great coffee machine which will continue to provide reliable service for decades to come....

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    Re: La Cimbali Junior R

    Thanks Java B

    The boiler is the biggest concern at this point - all the rest of the machine is pretty much ok - nothing that a few new bits wont fix at modest cost. I have completely disassembled it now.

    Heres the boiler. Note the white/green growths around where the HX neck enters the boiler cylinder. Also there seems to be similar growths on a number of the other boiler external joins. The HX neck appears to be pressed into the boiler somehow.

    Im figuring the only way to really get on top of this problem is to first clean/descale the thing, and then send the boiler off to have all these joints brazed.

    Has anyone seen this problem before, and perhaps can comment on the best way forward/solution?

    Cheers

    Slowdown


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    Re: La Cimbali Junior R

    Slowdown,

    That little forest of white and green crystalline growth is not unusual around the joints on hot devices (boilers in hot water services, coffee machines etc.

    It is caused by some weeping from the joint which contains some calcium salts as well as other salts which attack the copper (very slightly). It forms a green / green-white coloured growth as the moisture evaporates due to the heat. It is often most pronounced near welds where the two parts are joined (uneven surface where the water can concentrate and a slightly different metal which promotes the chemical reaction at that spot. The fact that coffee grounds also collect around these places makes a bed for the water to lie in and attack the surroundings as well.

    Although it looks pretty bad, after a thorough descale and clean, you will almost certainly find the underlying metal and joint quite sound. The amount of corrosion is usually very small even though the effect looks quite dramatic.

    The boiler only contains about 1 Bar of pressure (14 lbs per square inch) so its not under much stress.

    Give it a good clean (soak it in hot water with lots of citric acid in a non metallic container) and see what it looks like afterwards. You probably wont need to do anything further (just check for weeping from the joints after assembly to prevent it happening again).

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    Re: La Cimbali Junior R

    Quote Originally Posted by JavaB link=1174998951/0#13 date=1175393229
    Slowdown,

    The boiler only contains about 1 Bar of pressure (14 lbs per square inch) so its not under much stress.
    JavaB, my understanding of pressures is that everything at sea level is subjected to 1 bar. Including boilers.

    But when heated, boilers are that 1 bar, PLUS an additional 0.9 - 1.1 bar. *So in fact, around 2 bar. *The pressure gauges ignore the first 1 bar and read pressure in excess of that.

    Still a small pressure as you say.

    --Robusto

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    Re: La Cimbali Junior R

    Quote Originally Posted by robusto link=1174998951/0#14 date=1175394846

    JavaB, my understanding of pressures is that everything at sea level is subjected to 1 bar. Including boilers.

    But when heated, boilers are that 1 bar, PLUS an additional 0.9 - 1.1 bar. So in fact, around 2 bar. The pressure gauges ignore the first 1 bar and read pressure in excess of that.

    Still a small pressure as you say.


    --Robusto

    Robusto...

    There is 1 Bar of pressure on both the inside and outside of the boiler due to the atmosphere.... so there is no differential pressure which causes stress due to the atmosphere - therefore it can be ignored.

    There is 1 Bar of pressure inside the boiler due to the vapour pressure of the steam contained therein.... This is not applied on the outside of the boiler.... so there is a differential pressure on the boiler wall of 1 Bar or 14 lbs / square inch.....and it is the differential pressure which textures the milk.

    For example...
    An open boiler taken to 300M below sea level (no effect)
    A closed boiler taken to the same depth - would be crushed...
    Its the differential pressure which the gauge measures - and will affect the boiler.

    However the boiling point of the water contained is affected by both atmospheric pressure and vapour pressure above the water - a total of 2 Bar -

    Have I confused you enough yet?

    Java " I love physics too" B

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    Re: La Cimbali Junior R

    Isnt that what I said? ;D ;D ;D

    --Ro "E=MC2" busto

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    Re: La Cimbali Junior R

    Quote Originally Posted by robusto link=1174998951/15#16 date=1175397690
    Isnt that what I said? ;D ;D ;D

    --Ro "E=MC2" busto
    Nope.... maybe its what you meant to say....

    The boiler... as far as stress is concerned.... as I said in:

    "The boiler only contains about 1 Bar of pressure (14 lbs per square inch) so its not under much stress. "

    is you ignore totally the atmospheric 1 Bar pressure.... it is as if it doesnt exist.... it affects nothing re stress... its not important..... and therefore doesnt get mentioned ;) ;)

    So your comment re combined pressure only affects the boiling point - not whether slowdowns boiler is safe or not.....

    There is one - and only one - circumstance where atmospheric pressure affects the boilers stress. If you allow the water in the boiler to cool, vapour pressure drops.

    If the vacuum valve fails- pressure in the boiler drops to near zero - the one bar atmospheric pressure will then crush the boiler (that is why you should always open the steam valve when shutting down your machine)- boilers are designed to contain positive pressure - they dont like greater pressure externally :( :(

  19. #19
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    Re: La Cimbali Junior R

    My point was not so much about stress -- but the fact that inside the boiler there is 2 bar of pressure.

    I think we are coming to the same point but from different directions.

    --- one of the first lessons my late science teacher gave was causing a vacuum in a tin can and us seeing how the 14lbs of external pressure crushed it.

    A boiler in equilibrium (with a vacuum break valve) has 14lbs (1 bar) of air pressure trying to "crush" it from the outside, and that is balanced by 14 lbs of pressure inside, resisting that. (forget about round and egg shapes being stronger for the argument)

    Seal the boiler, set it to 1 bar and release steam. That "1" bar is then actually 2 bar. The original 1 bar of equilising air pressure, plus the additional 1 bar being applied by steam.

    Yes, I know the first bar is cancelled out by the atmospheric pressure, and the differential is therefore just one. But nonetheless, the pressure within the boiler is 2 bar.

    --Robusto

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    Re: La Cimbali Junior R

    Good luck with this challenge, once the boiler is soaked, descaled and buffed youll have a better idea of what needs doing, probably not much.
    I think home brew shops are the best sources of the large amounts of citric acid youll probably need. ;)

    One item to be sure to service is the valve groups inside the steam tap. if the seals become worn steam will leak through and the whole tap assembly will need replacing at about $110. Its the same setup with tthe hot water tap although this is less likely to be worn, Coffee parts list the required bits.

    other likely items would include pressurestat (complete or just diagphram), vaccuum breaker valve and of course all new cup washers, orings etc etc, solenoid valves are probably one of the few other expensive bits that may give trouble

    btw what year is it, Im thinking maybe late 1980s?

    for $200 you cant go wrong, although the parts bill could add up :o
    Quote Originally Posted by slowdown link=1174998951/0#12 date=1175388573
    Thanks Java B

    The boiler is the biggest concern at this point - all the rest of the machine is pretty much ok - nothing that a few new bits wont fix at modest cost. I have completely disassembled it now.

    Heres the boiler. Note the white/green growths around where the HX neck enters the boiler cylinder. Also there seems to be similar growths on a number of the other boiler external joins. The HX neck appears to be pressed into the boiler somehow.

    Im figuring the only way to really get on top of this problem is to first clean/descale the thing, and then send the boiler off to have all these joints brazed.

    Has anyone seen this problem before, and perhaps can comment on the best way forward/solution?

    Cheers

    Slowdown

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    Re: La Cimbali Junior R

    Quote Originally Posted by robusto link=1174998951/15#18 date=1175401101
    My point was not so much about stress -- but the fact that inside the boiler there is 2 bar of pressure.

    I think we are coming to the same point but from different directions.
    --Robusto
    Yep, we are looking at the same problem from different angles. I was purely concerned for the strength of the boiler - and if it had been compromised by the "corrosion".......

    As such it is all about stress on the joints etc.... and are they strong enough... so to quote:

    "Gauge pressure is a critical measure of pressure wherever one is interested in the stress on storage vessels and the plumbing components of fluidics systems."

    Which is why I say 1 Bar - which is gauge (or differential pressure) not absolute pressure. The statement "containing 1 Bar" means it is "holding in fluid and / or gas which is exerting a net 1 Bar of pressure on the walls of the container...." the other 1 Bar isnt being contained but exists everywhere at sea level.

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    Re: La Cimbali Junior R

    Great news Java B - I was starting to get a bit downcast about this issue. While not wanting to get too in front of things, its a relief to think that this stuff on the boiler could just be situation normal at this point.

    So, its off to get some food grade citric acid.... Thanks for the advice re sourcing this Mauricem, and also the other little pointers from experience!

    I read somewhere that the best ratio is around 1.5 tablespoons of citric acid for every litre of water. Any seconds on that?

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    Re: La Cimbali Junior R

    Quote Originally Posted by slowdown link=1174998951/15#21 date=1175403515
    So, its off to get some food grade citric acid.... Hmmm, now thats a good question - wheres the best place to get that - I assume a supermarket?

    I read somewhere that the best ratio is around 1.5 tablespoons of citric acid for every litre of water. Any seconds on that?
    Brewing shops often sell it a bit cheaper as well.... but supermarkets do stock it.

    Is used a ****LOT***** more than the recommended dose for descaling a small boiler "in situ". I threw in just about as much as would dissolve in the water. Its not very strong and is totally food safe. It will take forever to descale at the concentration you mentioned above.

    By the way, the pros (commercial machine repair facilities) use hydrochloric acid baths to descale - heaps more powerful, more dangerous to handle - and not food safe (so lots of cleaning after descaling).

    Good luck!

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    Re: La Cimbali Junior R

    Phew... didnt realise we were on page 2 already... so apologies for being a bit slow on the uptake...

    OK, off to the brew shop for supplies, then LOTS in hot water.

    BTW Maurice M, the only date I have been able to find was on a little tag on the back of the pressure gauge, which had 87 stamped on - this might be a date that sources the pressure gauge, and could be a pointer to the machine age?

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    Re: La Cimbali Junior R

    A couple of issues re the group head.

    There is a large allen keyed nut that appears to screw into the grouphead - before I apply serious force to loosen this, can someone confirm that this indeed a removable item. (My kingdom for a workshop manual!)

    Second, the silicone straw that draws water out of the HX is connected to a male threaded copper nipple that screws into the grouphead. It disintegrated on attempted removal - Im off to buy an easy out - but this is quite a serious issue at this point - Ill need some luck to get this out.

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    Re: La Cimbali Junior R

    slowdown,

    The "nut" actually blanks a hole that is drilled into the casting to allow the water ways to be machined......

    It can be removed...... but probably doesnt need to be (given your problem already....)

    Did you soak the unit in descaler prior to attempted disassembly? Scale locks threads as solidly as superglue..... the citric acid will slowly seep in and remove the scale - and then the assembly will come apart a lot easier.

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    Re: La Cimbali Junior R

    No, that was a mistake.... Ill do the descale before I attempt the easy out. :-[

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    Re: La Cimbali Junior R

    I recently bought one of these. I have not recieved it yet, it looks a little newer from the outside but that ,may mean nothing fingers crossed.
    WA is so full of lime, being and old Bunbury boy. Looks not to bad considering.
    Good luck with it, it will be more satisfing being a bit of a project.

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    Re: La Cimbali Junior R

    Progress not good - huge problems getting the scale off - despite using 7% HCl acid.

    Managed to do more damage trying to get one of the pipes off the boiler (leaking joints make a scale cement inside).

    So that is two bits that are a headache (the other being the snapped off HX straw).

    So I might be a good source of parts for your machine morningshot!

    Anyway, Ill keep going, but the prognosis is not good for this one. Ill have to put it down to a learning experience.

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    Re: La Cimbali Junior R


    Slowdown, dont lose heart. It sounds like a tougher restoration though. For the scale, try to find someone with a bead blaster to cut through it first. Then use hot citric acid to remove whats left.

    The HX units are replaceable and I believe coffeeparts sells them.

    As for the pipes, youd best use an impact wrench and some penetrating oil. Just dont use brute force or youll bend the boiler and possibly crack the joints. Maybe try and find a coffee machine restoration place and ask for some friendly advice... All of this stuff is serviceable, maybe just not as simple as first thought.

    Cheers,

    Mark.

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    Re: La Cimbali Junior R

    Scale was no problem really - a coupla days in 7.5% HCl put paid to it - EXCEPT in some of the threads where there had been previous slow water leakage - leading to a scale deposit cementing the thread.

    (On the issue of 2 days in 7.5%, note that the HX is looking a bit pitted now - not sure whether this was there prior, or whether this is the effect of the HCl!).

    I have had to give up on some of these cemented threads... I think this is a lesson for young players - its almost impossible to loosen threads which have been scale cemented in this way - even after 2 days in a (strong) acid bath. Easy to damage the boiler connections....

    Anyway, I am near to the point of putting it back together. I intend to do a rough re-assembly job with just new seals and a new element - to see if the boiler is holding water. If it does, the next step will be to address the HX issue and get a new 3-way solenoid.

    Time will yet tell whether the Junior will ever pull another shot...

  32. #32
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    Re: La Cimbali Junior R

    Hi Slowdown,

    I was cautious using the HCl solution as well; when I did the Bo-Emas boiler I physically chipped/scraped away as much scale as possible between soakings; the advantage of a removeable end plate. A soak in an acid solution certainly doesnt seem to be a panacea for scale removal. I was nervous having dis-similar metals/alloys (brass/copper/silver solder) in contact with each other for extended periods in such an aggressive solution.

    My latest project had a lot less scale, and of a sort that seemed to be more easily removed. That being said, it has still not actually dissolved in the HCl bath, but sits on the bottom of the container like soggy cornflakes.

    Ive come to the conclusion that as long as scales not blocking pipes, or breaking free to block jets etc, I can live with it being there.

    No advice to offer about the cemented threads other than whats in the archives, but Id be interested to hear how you get around it eventually.

    Good luck and dont get disheartened,
    Phil


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    Re: La Cimbali Junior R

    Sorry to take so long to reply.

    Still havent picked mine up.
    I would keep going.
    I have always liked this site for stuff
    coffeeparts.com. particularly as the Bl....dy Aussi dollar is so strong.
    although the Sydney based dealer, I forget the name, also seems good.
    Best of luck

  34. #34
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    Re: La Cimbali Junior R

    Finally got mine and now going.
    I suspect that the pressure guage is faultly but I dont want to enter in the conversation of how they work. and if they are faulty, incase i start that argument again.
    New pump new elementand a bit of elbow grease.
    Cant say that Ive mastered it, I can pull the odd good shot, but not 90% like I could with silvia.
    Ill just have to stick with it.

    N.B.
    Image resized to 640x480 for easier viewing in a browser,
    Mal.



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    Re: La Cimbali Junior R

    Sure is a classy setup there MS 8-),

    Looks great and time will work its magic to ensure that consistently excellent shots are just a short journey away. Happy brewing :),

    Mal.

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    Re: La Cimbali Junior R

    Thanks
    Im now getting the swing of it. A few hours and a kilo of beans.
    A cooling flush is essential, and having the pressure guage, now accurate, has allowed me to get the temps right.
    My first HX machine, so a steep learning curve.

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    Re: La Cimbali Junior R

    Looks in very good nick Morningshot - clearly better than mine. Congratulations.

    An update on my restoration:

    After an extended break due to longworkhoursitis, I have recently been able to refocus on Chumly. I think I have now solved the two outstanding problems from the dismantle/descale.

    First of all, I was able to source a new HX straw from Supreme Coffee Machines here in Perth (the local La Cimbali agent). It was then a simple matter to drill out the group head hole with the old broken off straw in it, tap into the old thread with a 10mm tap, and then re-insert the new straw. Heres a piccy below of the new straw in situ, with the old straw for comparison.

    More difficult was fixing the splits in the boiler caused by trying to take the bottom pipe off (I think I omitted to mention that above... was cemented by scale, and didnt come off despite nearly 2 days in HCl... was pretty devastated to discover I had twisted the boiler thread assembly and split...).

    Anyway, I used Comweld 265 solder to fix this. It is a pure silver solder with no cadmium or lead in it, so is food safe. It is available from most welding suppliers that stock CIGWeld products. It has a low melting point so is reasonably easy to apply with a decent soldering set up. I gather that donkey engine enthusiasts make their own boilers from scratch with silver solder - so a split boiler is not necessarily a death sentence! It would even be possible to put a copper patch over a larger split methinks.

    Attached pic in the next post shows my solder collar which covers up the splits. Not pretty, but did the trick (I have re-assembled from this and tested with success).

    So, now I know the Chumly will work again, I have fully stripped down again. I have just cleaned up the frame, de-rusted, and sprayed it (had to be done, given the level of rust).

    I am about to order the other bits and pieces I need to complete the job.

    Questions at this point are:

    - should I put a new Serai PS in or just go straight to a PID - if so, what sort of PID do I need?
    - should I stick with the Ulke vibe pump, or is there some better solution?

    Given that Chumly will never be concours, I think it might be worth considering these potential mods. Any suggestions greatly appreciated!






  38. #38
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    Re: La Cimbali Junior R

    Heres the soldering piccy.


  39. #39
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    Re: La Cimbali Junior R

    Gday SD,

    Good to see that youre nearly back into action there mate. If youre contemplating PID for a HX machine, its not really the best way to go and there is an in depth discussion about this very topic here.... http://coffeesnobs.com.au/YaBB.pl?num=1174149362/0 that is a very good read.

    If it was me in your position, Id just be going for a Sirai p/stat which are built like tanks incidentally, and use it to switch an SSR to power your boiler element, will last forever that way with the occasional diaphragm replacement as your only concern. All the best,

    Mal.

  40. #40
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    Re: La Cimbali Junior R

    Thanks Mal - that thread made sense - no point in stabilising a 2 degree variation in the HX boiler. 8-)

    So, how does one put an SSR on a Sirai? Is there a thread somewhere that explains what SSR might suit and how to put it in?

    It would seem I should be able to use the existing Sirai (replacing the diaphragm) and then use the SSR to sidestep the Sirai relays (Chumbly is down to his last one)?

  41. #41
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    Re: La Cimbali Junior R

    Quote Originally Posted by slowdown link=1174998951/30#39 date=1188133437
    So, how does one put an SSR on a Sirai? Is there a thread somewhere that explains what SSR might suit and how to put it in?
    Its fairly straight forward SD..... Basically, instead of the p/stat contacts switching the boiler element directly, you use them to switch the SSR (need a 240V AC Input SSR with a 25-40 Amp Output) and the Output of the SSR to switch the boiler element. That way the p/stat contacts will last practically forever, as will the SSR, with the p/stat diaphragm being the only component that will wear out.

    Quote Originally Posted by slowdown link=1174998951/30#39 date=1188133437
    It would seem I should be able to use the existing Sirai (replacing the diaphragm) and then use the SSR to sidestep the Sirai relays (Chumbly is down to his last one)?
    Yep, that would be the best thing to do. You can buy SSRs from most industrial control suppliers like this one, or this one. The main thing to be careful of with SSRs is that you need to make sure that you mount them direct to an unpainted metal surface so that any heat loss generated will be conducted away, using any of the thermal heatsink compounds that are readily available these days as an interface.

    Have fun with your mod....
    Mal.

  42. #42
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    Re: La Cimbali Junior R

    Thanks for that Mal.

    Hmmm, I see that a 25 amp SSR would set me back $30 (assuming one doesnt need to buy the compatible heat sink bit, an extra $30).

    Trusty Wiki and its links (http://en.wikipedia.org/wiki/Solid_state_relay) suggest that SSRs are not infallible. This Wiki recommeded link - http://zone.ni.com/devzone/cda/tut/p/id/4125 - suggests that SSRs are not as robust as electromechanical relays. Much like reed relays, they are highly susceptible to surge currents and damage when used at signal levels above their rating. Although there are no metal contacts to weld, damage to the MOSFET can render the relay unusable.

    Given that a new Sirai is only around $95 from Coffeparts, gives 3 lives, doesnt require scraping back my new paint job, *and doesnt require a rewire (electrickery is not really my thing) I think Ill stick with the vanilla Sirai.

    Thanks again for your informative advice.

  43. #43
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    Re: La Cimbali Junior R

    SSRs will last indefinitely, but its always a good idea to employ one with a rating well above the actual current of the element. For instance, on Miss Slvia, which draws about 4.7 amps, youd use a SSR about 5 times that rating.

    But having said that, there is nothing wrong with doing what you propose, Slowdown: a new SIRAI pressurestat directly switching the element.

    It should last years, and there are spare unused contacts in case the ones wired to the element burn out.

  44. #44
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    Re: La Cimbali Junior R

    Quote Originally Posted by slowdown link=1174998951/30#41 date=1188217237
    rusty Wiki and its links (http://en.wikipedia.org/wiki/Solid_state_relay) suggest that SSRs are not infallible. This Wiki recommeded link - http://zone.ni.com/devzone/cda/tut/p/id/4125 - suggests that SSRs are not as robust as electromechanical relays. Much like reed relays, they are highly susceptible to surge currents and damage when used at signal levels above their rating.
    This advice was probably relevant 10-15 years ago but a properly installed adequately rated SSR is super reliable and if you employ the safety factor mentioned by Robusto above, mounting direct on to a metal section of the frame or panel-work will be a sufficient heatsink, no need to purchase an additional one....

    Mal.

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    Re: La Cimbali Junior R

    The internal pressure is around 2 bar absolute as you say. The external is 1 bar of atmosphere so the net pressure on the boiler trying to blow it up is 0.9-1.1 bar (at sea level). If your interested there is a good table at
    http://www.engineeringtoolbox.com/saturated-steam-properties-d_457.html
    showing absolute pressure of steam vs temperature. Remember to take off the external air pressure
    http://www.engineeringtoolbox.com/air-altitude-pressure-d_462.html
    for the net boiler pressure.
    I have been looking at this to get an estimate of my boiler temperature fluctuations from my pressostat switching pressures. Just working out if I can get a temperature probe in my level probe hole of vac break hole so I can fit an internal embedded PID controller.
    Do you know roughly the diameter of your boiler, any idea of the copper thickness.

    In regards SSRs, we find they have a life of 1-2 years generally in our environmental chamber control even when well under rated. For some reason they get stuck on at times (i.e. your boiler will keep boiling). We also find that if the input is left floating by the switching circuit in the off state that the relay can randomly switch on and off (240v ac input) so we use a dummy load across the input to ensure the input terminals have no potential in the off state.

  46. #46
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    Re: La Cimbali Junior R

    I think all of the anectodal evidence from those who have installed a PID on their Silvias alone would confirm the long life of the SSR. Heat can be a problem, but not if the SSR is of high amperage, and, as Mal says, stuck to a metal baffle within the coffee machine to conduct it away.

    I would definitely not mess with the vacuum break valve to convert it into a well for a themocouple. The valve is there for a purpose and does its job quietly, efficiently, automatically, expelling air which would give a false pressure on startup...and drawing it back in to equalise internal and external pressure on shutdown.

    Attaching a thermocouple on the boiler will instantly show the temperature rise and fall as the pressurestat switches the element.

    It may not be the ACTUAL temperature, but it will show the temperatue change if that is what you are looking for.

    And it should work out at 1º C per 0.1 bar. So, figure on a 2ºC deadband. That is an excellent result.




  47. #47
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    Re: La Cimbali Junior R

    Quote Originally Posted by steveedmonds link=1174998951/30#44 date=1188235245
    In regards SSRs, we find they have a life of 1-2 years generally in our environmental chamber control even when well under rated. For some reason they get stuck on at times (i.e. your boiler will keep boiling). We also find that if the input is left floating by the switching circuit in the off state that the relay can randomly switch on and off (240v ac input) so we use a dummy load across the input to ensure the input terminals have no potential in the off state.
    Yes, if there is any doubt about the quality of ones power supply, then you really do need to look at properly configured snubber networks, line conditioning, or a separate power supply (via an internally wired txfmr and rectifier output). Ive used SSRs and related technology in all sorts of electrically noisy, and horrendous physical environments in both light and heavy industrial applications... when the installation has been properly engineered, longevity in service was never an issue.

    Where one is going to be using SSRs with an AC Input in a domestic situation, if the local power supply is such that floating voltages above the turn-on threshold are occurring, then that would be of great concern and indicate that the installation should be investigated and rectified by properly qualified personnel, as a matter of personal safety.

    Cheers,
    Mal.

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    Re: La Cimbali Junior R

    Most of that discussion went clear over my head - SteveEd the diameter of the boiler is 13 cm and the copper thickness is around a mm *or perhaps 1.2.

    I think an SSR seems like a really good idea - powering up Ciambli today in further testing mode and watching the Sirai switch, there is quite a spark every time it switches - so its not surprising the points wear out with time.

    That said, I have discovered that my Sirai is only half way through the life of the first of the three points sets - the other two were just bent at 45 degrees for some obscure reason - nothing that a bit of attitude adjustment with the pointy nose pliers didnt fix quick smart (power off of course!). Subsequent, I was chuffed to see that the Sirai had the pressure oscillating nicely between 1.1 to 1.3 bar on the dial - so all good - and no doubt giving the 2 deg C variation you allude to Robusto.

    I think I will move to an SSR a bit further down the track - perhaps when I am on my last relay. Mind you, that might be awhile - the existing Sirai cover is a rust bucket, implying age, yet it was still on its first relay. Reliable indeed.

    I still think I am going to need to invest in a new pump. The existing Ulka does seem to work, but is pretty slow in its flow and seems to lose pressure easily (like, put my finger over the outlet pipe and can stop the flow completely). It certainly cant push water into the boiler once it is at operating pressure, and finds it hard to stop the HX water turning to steam (cooling flush - what cooling flush?).

    Anyway, again, I guess sticking with the Ulka is a reasonable idea. The idea of changing this aspect seems a bit silly with reflection. It would be good to get to the coffee stage before Xmas!

  49. #49
    Mal Dimal's Avatar
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    Re: La Cimbali Junior R

    Quote Originally Posted by slowdown link=1174998951/45#47 date=1188299442
    I have discovered that my Sirai is only half way through the life of the first of the three points sets - the other two were just bent at 45 degrees for some obscure reason - nothing that a bit of attitude adjustment with the pointy nose pliers didnt fix quick smart (power off of course!). Subsequent, I was chuffed to see that the Sirai had the pressure oscillating nicely between 1.1 to 1.3 bar on the dial - so all good - and no doubt giving the 2 deg C variation you allude to Robusto.
    The commercial Sirai units are indeed very reliable and rugged units..... The reason for 3 sets of contacts is that in a normal commercial installation the usual power supply is 3-Phase and the Sirai is specified to withstand this level of operation so in a 1-Phase domestic situation, only one pair of contacts is needed to switch a single element. On my somewhat mature Bezzera MiniBar, the p/stat has only one set of unused contacts left so an SSR is targeted to augment these.

    Sounds like your p/stat is working very well though with that 0.2 Bar dead-band which means the diaphragm must be in good condition. Genuine Ulka pumps can be acquired from CoffeeParts for very reasonable cost so if it looks as though the pump is cactused, it will be a simple change-out routine for you..... And, hopefully you will be into truly great coffee well before Xmas :),

    Cheers,
    Mal.

  50. #50
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    Re: La Cimbali Junior R

    Well the Chumbly is in operation. This and the following show photos of (unfaired) functioning unit and its installation in the Storeroom Cafe (artwork courtesy of Emma).

    Getting used to pulling shots with it. Still on the learning curve, so yet to beat the quality with my La Pavoni Europiccolo on a consistent basis. Need to finish off putting the fairings back on - but it seems to go just as fast (painting the Sirai cover ducati red helps Im sure)!

    [img][/img]




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