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Thread: Isomac Mondiale - shot boiler element?

  1. #1
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    Isomac Mondiale - shot boiler element?

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    My Isomac has flipped the safety switch in the box, it happened once about 2 months ago (one off, let it sit and it went fine after an hour or so), but yesterday morning it set the RCD switch off three times in a row. I tried another power outlet, same result.

    I've pulled the sides and back off the machine, and sat a multimeter on the boiler elements (with the clips taken off). It read 0, which indicates a short in the boiler element. Is that correct? I'll be honest, electrical terms confuse the heck out of me.

    Every other switch I put the multi meter on gave me a 1.00 reading.

    Am I on the right track?

  2. #2
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    While it is disconnected from the power, are you getting a short between either element posts and the boiler. This would indicate a dead heating coil as well. This is what trips the RCD I think.

  3. #3
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    Hi bmawebb,

    Your diagnostics sound correct. If you have pulled both lugs off the heating element and the resistance is 0 Ohms then you have a short circuit across the element and your RCD circuit breaker is tripping on overcurrent. Just FYI this isn't technically the RCD Component of the breaker which detects current leaking to Earth, but it is likely tripping on over current because of the very low resistance due to the following relationship:
    Volts=Current*Resistance
    On a working 2000W/8.3ish Amps heater element:
    240=8.3Amps*Resistance
    Resistance =29ish Ohms

    For your example:
    240=(Amps) * 0
    Almost infinite current so a standard 10 or 20Amp breaker will trip every time.

    Hope this makes a bit of sense.
    Thanks,
    Chris

  4. #4
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    thanks Gitney.

    I'll order a replacement boiler element and see how we go replacing it.

    I'll keep this thread updated.

  5. #5
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    Hi bmawebb,
    Just a quick thought. I hope your multimeter is OK. Might be worth checking ideally a resistor that you know the resistance of, or even an incandescent light bulb (40W bulb should have a resistance of 1200Ohms).
    Thanks,
    Chris

  6. #6
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    I've thought some more, and given my limited confidence in my own knowledge, I'm going to box it up and send it off to a professional in Perth for a service and parts replacement.
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  7. #7
    Mal Dimal's Avatar
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    Great decision "bmawebb"...

    Always best to play it safe with electrical issues...

    Mal.
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  8. #8
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    No one, in my experience, has ever regretted getting a new heating element.

  9. #9
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    Ok, a good number of weeks and dollars later, and I've set the machine back on my bench. Twenty minutes of running time and the boiler pressure is showing 0, but the pump operates when I turn on the handle. water is lukewarm. One quarter turn of the thermostat, and now I have no heat at all. Pump still works when I lift the handle.

    I'm bitterly disappointed after five weeks and $1100.

  10. #10
    Senior Member sprezzatura's Avatar
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    What did they do to it?

  11. #11
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    Where did you send the unit for repairs? Could be helpful for others

  12. #12
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    I'm not disclosing where it went until I can talk to them today.
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  13. #13
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    Kudos for giving them a chance to explain / discuss the issue before any 'naming and shaming' - it's always good to seek and if relay a balanced perspective.

    My nine year old Mondiale has had three elements fail over the time I've had it, but it's always been a routine repair - I'm interested to understand, what cost $1100?

    Cheers,

    -A-
    Last edited by -Alchemist-; 18th April 2016 at 12:16 PM. Reason: typo
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  14. #14
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    I hope it all goes well for you

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    Okay, I've printed off the receipt to have a good look.

    As the tech discussed with me over the phone, the whole boiler needed replacing ($460) plus the heating element ($85) plus a complete overhaul service, showerscreens, solenoids, probes, valves and labour. There were some pinholes in the boiler, and the fittings had seized. They tried to revive it, but it wouldn't seal.

    In their favour, it did travel the 750km there and the 750km back in a non original box, though I packed it pretty well.

    I've called this morning and told the tech what happened when I turned it on, and that there's pump working but no heat in the boiler. He's under the impression that it's the pressurestat (thermostat?) and is sending another one to me at no cost to install myself.

    I'm happy with that result, though I'm very grumpy that I received a kilo of roasted beans the morning it died, so they're sitting unopened in my cupboard 5 weeks later... and likely to have peaked already.

  16. #16
    Mal Dimal's Avatar
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    Quote Originally Posted by bmawebb View Post
    There were some pinholes in the boiler, and the fittings had seized. They tried to revive it, but it wouldn't seal.
    Does the Mondiale use a stainless steel Boiler mate?

    Mal.

  17. #17
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    Yes, yes it does.

  18. #18
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    Rightio mate...

    You will need to take special precautions with filtering the water for your Mondiale.

    Basically, you need to remove all traces of Chlorine and its compounds from the water before it gets into the Boiler. Chlorine dissolved in water creates havoc with s/s Boilers, as the action of high temperature combined with pressure, will cause pit corrosion and/or stress corrosion on the internal surfaces of the Boiler. Plenty of info can be found on the Net as to why this happens and my recommendation would be to talk to Tech's at Bombora or one of our Site Sponsors who have the specialised knowledge in this area...

    Mal.
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  19. #19
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    Thanks Mal.

  20. #20
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    FWIW, we use filters from Unicorn. They seem to remove all chlorine and other unwanteds. Based in Osborne Park. They have various systems available.

  21. #21
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    So the new pressurestat arrived, and I carefully removed the old one, replaced it with the new one and.... Nothing.

    I'm into this now for a much as I paid for it, and the shipping to and from Perth is around $350. I'm going to have to wait until I go back down there again and can see it working on their bench.

    Colour me frustrated.
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  22. #22
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    Seeing as they fit a new element, perhaps they didn't tighten the wiring down firmly and it came loose in transit?

    Have a look at the element and wires and check if they're loose or damaged in some way.

  23. #23
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    Checked all the wires, nothing is loose


    Team the multimeter over the exposed lugs on the boiler element... And got an infinity reading. Last time I got 0.

    So, is my boiler element buggered?

  24. #24
    Mal Dimal's Avatar
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    Definitely should read somewhere in the low Ohms range on a Multimeter.
    Do you get Zero on the meter when you short the leads together?

    Mal.

  25. #25
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    Yep. And I tested a 40w light globe and got 11750 ohms
    Last edited by bmawebb; 23rd April 2016 at 08:53 PM.

  26. #26
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    It's probably got a 1300W element or thereabouts so you would expect to see around 45 ohm.

    Possibly when they fit the new boiler they wired up the element for the initial power up when the boiler was completely dry. The autofill circuit should cut power to the element whenever it detects low water however I did a boiler replacement on a La Nuova Era Cuadra the other day and the element got power when the boiler was filling.

    This is bad news on a completely empty boiler as the element will be heating nothing but air for 5-10 seconds. This can harm the insulation around the element and lead to premature failure.

    If this happened and they didn't perform several heat cycles on the new boiler, which should be done to check fittings and seals, then the element might have fried when you powered it up.

    When you got the machine back and first switched it on, did the pump automatically switch on and stay running for a long time? This would indicate the boiler was empty and the damage could have occurred then.
    I'm not sure of the autofill logic on an Isomac machine, it should cut power to the element when filling but maybe it doesn't.
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  27. #27
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    The pump kicked in for about a 6 second cycle for about 10 cycles, which took about 3-4cm from the water tank.

  28. #28
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    Okay, I'm still struggling. I've pulled the new element out, it measures infinity resistance.

    I'm still dialoguing with the repair guys who have been pretty helpful given the distance between us.
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  29. #29
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    Quote Originally Posted by bmawebb View Post
    Okay, I'm still struggling. I've pulled the new element out, it measures infinity resistance.

    I'm still dialoguing with the repair guys who have been pretty helpful given the distance between us.
    Sounds like a new element is in order.

  30. #30
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    Forgot about this thread, sorry. Infinity resistance indicates an open circuit. I have a feeling, like I mentioned before, it was connected up when first filling which has caused the damage when the element was exposed to air for a while.

    I'm a little confused as to why they have put teflon tape and an ill-fitting silicone o-ring on the element. A teflon gasket should be used to seal the element.

    Regardless, you need a new element and I would suggest the correct element gasket as well. I think it's a 1" teflon gasket.
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  31. #31
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    Yes, very unprofessional with the tape.

  32. #32
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    Quote Originally Posted by noidle22 View Post
    I would suggest the correct element gasket as well. I think it's a 1" teflon gasket.
    Gaskets for this type of element are usually 1.25", don't think a 1.0" gasket will fit...

    Mal.
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  33. #33
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    We usually use this one here
    ECM Giotto Heating Element Gasket - Di Bartoli

    Regards
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