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Thread: La Cimbali M28 Select

  1. #1
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    La Cimbali M28 Select

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    I found a 2 group Cimbali on GTree last week for $150 and couldn't resist the temptation. Picked it up on Saturday and couldn't wait to try it out. I would like to upload some photos and the manual but the site won't let me.

    I fed the water from a bucket and connected the 240 v 15A power connection to a 15A socket. I turned the main switch to position 1 / water fill and nothing happened so I pressed the button on one of the group control and the pump fired up. Water squirted out of the end of the pump so I turned it off quickly.

    I pulled the pump out and removed the circlip holding in the end plate and found the seal was not fitted right so I reseated it and put the end plate back on. I tried the pump again and the leak was fixed but it was making a fair bit of noise. Mr google came to the rescue when I found a cause of this with a procon pump can be leaking seals on the inlet filter nut and pressure regulator nut. Both of these looked a bit worn and flattened so I replaced them from my trusty Aldi o ring collection. This fixed the noisy pump.

    I then found that the boiler was already full of water so that was why it wasn't filling. I took the fill sensor out to give it a clean and drained the boiler to see what was in it. The boiler water was very clean but smelled a little. I put the sensor in and turned the machine on and the boiler filled and cut off the pump as expected. I then did a drain and refill 2 more times with filtered water.

    Next I turned the heater on and she started pulling current about 14A which is on spec for this machine. After a while the pressurestat turned off the boiler but the boiler pressure gauge was stuck on 0.5 bar. I turned it off and drained the steam then removed the pressure gauge and opened it up. It had a lot of coffee grounds around it but I put it in descaler and cleaned it up and after reinstallation it worked again.

    I adjusted the pressurestat to 1.2 bar and let the machine heat up. When I tried pulling water from the groups the flow was very slow and intermittent. This machine has filters and jets inline with the water feed to the groups and these were both severely blocked with scale and dirt. I dropped them in descaler for 4 hours and they cleaned up fairly well. Both groups now dispense water reliably.

    At this point I couldn't resist pulling a shot so I just loaded up the filter with 18.5 gms of coffee and pulled a shot. It extracted 37 gms in 19 seconds so the pressure must be ok. The shot tasted ok but I didn't drink it as I hadn't properly flushed the heat exchangers yet.

    I'm not sure whether to do a full restoration on it or not. Do you think it's worth the effort to pull it all apart or just do a descale in situ?

    mcudogs
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  2. #2
    Senior Member artman's Avatar
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    Good work! I wouldn't pull it apart if not required, just clean/descale as needed and enjoy the brews.

    Don't forget coffee parts have a heap of parts for these beasts.

    Cheers
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  3. #3
    Super Moderator Javaphile's Avatar
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    Welcome to CS and to the world of Cimbali!


    Java "Loves his Cimbali" phile
    Toys! I must have new toys!!!

  4. #4
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    Thanks Java and Artman I put an order in to Coffee Parts for all filters and seals. I will have a look inside the boiler to see the level of scale.
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  5. #5
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    I received the Coffee Parts order this afternoon (great delivery time) and fitted the replacement gicleurs and filters. The flow rate from the head was greatly reduced so I checked the orifice sizes of the old gicleurs and they are about 1.0mm where the replacement units are 0.5mm. I will have to set up a pressure gauge on the portafilter to see what the pump is putting out. Can I measure the pressure at the pump or is it meaningless?

  6. #6
    Senior Member artman's Avatar
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    Best to measure at the group, preferably with appropriate flow.

    Cheers
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  7. #7
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    It looks like the pump needs an overhaul, I took the pump outlet hose and blocked it with my finger when it was pumping. It was fairly easy to stop the flow completely. I adjusted the pressure to maximum but it made no difference.

    Does anyone know where I can get a Procon pump repaired?

  8. #8
    Senior Member artman's Avatar
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    I havent researched repair of the pumps but you can buy new pump only and use the old motor (assuming its good). I would think if it is repairable, it would only be a DIY proposition as the labour cost would probably make it more economical to buy a new pump instead instead of overhaul?

    Cheers

  9. #9
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    I can buy a parts kit from the USA for $35 but postage is $65 all up about $AU140 so unless I can get a parts kit in Australia it's not worth it.

  10. #10
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    I found an obscure reference to a company in Australia called Roerhlen that are supposed to be the Australian reps for Procon, email sent. Let's see what they can do.

  11. #11
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    M28 Before Pictures

    Before cleanup and descale.
    Attached Images Attached Images

  12. #12
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    Roehlen Industries will repair the pump for $105. This involves a full rebuild including replacement of all wearable parts with warranty so I am going ahead with the repair.
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  13. #13
    Mal Dimal's Avatar
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    Sounds like a very worthwhile thing to do...

    Mal.
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  14. #14
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    To descale or not to descale a boiler, that is the question

    I've done a lot of searching on this subject and found a lot of different opinions. Some say you shouldn't descale a boiler unless it is really bad.

    Based on the attached picture of scale in the boiler, do you think I should descale the boiler?

    Don
    Attached Images Attached Images

  15. #15
    Mal Dimal's Avatar
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    To be honest Don,

    I'd think seriously about removing the boiler altogether and descaling outside of the machine proper. Probably start out with a good hose-out to remove all the loose stuff first, then hit it with a commercial quality descaler; plenty of our Site Sponsors will have it.

    After the boiler is spick and span, it would then be worth checking all related pipework and fittings and descaling as necessary. Best to do all this now and then stick with decent water filtering to prevent a repeat. This is what I'd be doing in your place anyway...

    Mal.

  16. #16
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    Thanks Mal, that sounds like a good idea. I was speaking to a coffee machine tech today and he said that if I had to descale it should be done outside the machine. He also said that a descale will often cause the element to fail later so I will make sure I remove it first.

    Don
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