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Boiler overfilling help!!

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  • Boiler overfilling help!!

    I have a la San Marco 85 16m single group. I have rebuilt it and it been running fine for the last 3 months but now the boiler overfills, but not with the pump filling it, it is filling really slowly and while switched off as well. Like the pump or inlet valve is leaking water through. For example when I switch the machine off at night the boiler level will be an inch under full and when I switch it on in the morning I have to drain water out because it's way above full!! Help please.

  • #2
    Hi there,

    those that know me well enough know that I always harp on why the water should be turned off to a plumbed machine every night in addition to it being electrically switched off. Here is another example of the "why".

    Well, the most obvious place to start if it were mine, would be to check if there is a small bit of "rubbish" lodged on the seat of the inlet solenoid valve, holding it open ever so slightly and allowing water creep into the boiler. That's a relatively easy fix.

    The much more sinister "I wouldn't bother fixing this" scenario is if it is determined that the creep is caused by a leak out of the heat exchanger... but that's just so you know there can be other reasons for this besides relatively easy ones to sort.

    hope that helps.


    • #3
      Also, as you probably know, the machine has a manual fill valve, the lever front right of the drip tray. This could also be the source of your errrant filling if the valve is stuck open or the seal has perished.


      • #4
        And... TOK wins the day. Big ol' crack in the heat exchanger!

        Lucky for me I have alternative plans and won't be needing it.... This is going to be one cool San Marco!


        • #5
          So it was cracked. How's it all going with the machine?


          • #6
            It's going well, I have ended up shoehorning in an extra boiler so I can do away with the heat exchanger, it was not viable to attempt a repair to it. So, I've cut some big holes in the tube wall, sealed the ends and made it part of the steam boiler volume. I've also turned the chamber that used to house the level probe into an internal small volume heat exchanger to pre heat water for the brew boiler. Also added a late model group with a stabilising loop, and a spring preinfusion chamber. Should be pretty sweet, attached some work in progress photos.

            This project will be up for sale when complete, and includes a powdercoat and full strip down/rebuild plus the extra hardware. It will be 10 amp still, plumb in, external rotary pump. Expressions of interest welcome at this stage, ETA 2 weeks, waiting on my custom element for the brew boiler.


            • #7
              Photos I attempted to insert into previous post....

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              • #8
                Kewl ! Good job mate.