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Thread: Rancilo Classe 6 refurb - overfilling issue

  1. #1
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    Question Rancilo Classe 6 refurb - overfilling issue

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Hi All,

    First time poster here.
    I managed to pick up a free Rancilio Classe 6 and another Rancilio EPOCA for $100 recently and have been doing the refurb on the classe 6.
    I've been using the EPOCA for parts and so far i have saved hundreds on parts already.

    I've stripped the Classe 6, descaled it and put it back together. i'm now onto the commissioning phase and this is where i have hit a road bump.

    When i turn on the machine, pump kicks in and fills the boiler and stops when it should. HOWEVER, when i start running shots through the grouphead, i noticed the boiler filling up too! It would do that until the boiler is overfull.
    I noticed the Fill Solenoid is always on, thus always sending water into the boiler everytime the pump is running. The solenoid valve would get hot after awhile. I'm assuming what is meant to happen is that the Fill solenoid will only be activated when told to do so (filling the boiler) and should be normally in the closed position?

    I removed and refitted the solenoid plug and can here it opening the valve everytime I refit the plug on. That tells me that the solenoid valve is not jammed open instead being told to open. I have also pulled the valve apart and have a look and there was nothing that could have been forcing the valve open.

    That leads me to the Fill solenoid plug. Would there be something wrong with the wiring that could make it active when it shouldn't?
    I hope this is not too confusing, my knowledge on electrickery isn't great.

    thank you!

  2. #2
    Senior Member level3ninja's Avatar
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    Something upstream of the plug must be switching the voltage to the plug on. It could be a welded relay or similar, or it could be something in the control circuit that is fooling the controller into thinking the tank is always empty.

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    Quote Originally Posted by level3ninja View Post
    Something upstream of the plug must be switching the voltage to the plug on. It could be a welded relay or similar, or it could be something in the control circuit that is fooling the controller into thinking the tank is always empty.
    the level sensor seems to be working. when i remove the connection to the level probe, the pump kicks in as it thinks that the boiler is empty and that it needs to be filled. when i reconnect the level sensor, the pump stops.
    i couldn't see a relay upstream, it does look like it has a connection to the control circuit and i agree with you that that is probably where the issue is. How do I best diagnose a fault on the control circuit?

  4. #4
    Senior Member level3ninja's Avatar
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    The electrical diagram I found didn't show any part of the CPU circuitry, so I can't pinpoint. However you could have your licenced electrician trace the control circuit that powers the solenoid coil back to see what it is switched by, and test that component to see if it is operating correctly.
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  5. #5
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    Quote Originally Posted by level3ninja View Post
    The electrical diagram I found didn't show any part of the CPU circuitry, so I can't pinpoint. However you could have your licenced electrician trace the control circuit that powers the solenoid coil back to see what it is switched by, and test that component to see if it is operating correctly.
    pulled the control board off and had a look. the capacitor on the filling circuit was showing low resistance ~10ohm compared to 20M ohm on the others. so replaced it with another capacitor from the other machine but again it is showing 10 ohm. so now looking a little upstream to the triac component. going to replace that this weekend and see how that goes. i hope that is the problem as i'm running out of ideas.

    if you guys are interested, i could post some pics of the rebuild so far.

  6. #6
    Senior Member Lyrebird's Avatar
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    Were these 10 ohm measurements in circuit?
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  7. #7
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    yes, it was showing 10ohms when measuring the capacitor on the circuit.

  8. #8
    Senior Member Lyrebird's Avatar
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    OK, then it's very unlikely that you are measuring the capacitor itself, much more likely the circuitry surrounding it. I'd guess you are actually measuring the output impedance of the level comparator circuit but I'd have to see the circuit to give a precise answer.

  9. #9
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    Quote Originally Posted by Lyrebird View Post
    OK, then it's very unlikely that you are measuring the capacitor itself, much more likely the circuitry surrounding it. I'd guess you are actually measuring the output impedance of the level comparator circuit but I'd have to see the circuit to give a precise answer.
    i think you are on the right track there. my elec engineer mate said the same thing. After replacing the triac, machine is working good now. no more overfilling issue! super stoked!
    thank you for all your inputs.
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  10. #10
    Mal Dimal's Avatar
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    Well done...

    Mal.

  11. #11
    Senior Member Jackster's Avatar
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    Good job tackling a onboard repair, without resorting to remove and replace mechanics



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