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Thread: Questions on machine operation.

  1. #1
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    Questions on machine operation.

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Gday all.

    I just joined up the other day.... gotta say I like reading and learning more than posting (always worried about looking like an idiot).... but on Andys advice Im just going to jump in and start posting.

    Ill start by saying that I did try the Search feature but really couldnt find similar questions and answers to mine.

    Ive finally been able to afford to buy a new machine and bought myself a new machine (that would be described on the these CoffeeSnobs forums as "pointy end"). Its had a few teething problems which have had me concerned me a little... but Im trying to tell myself to chill out and relax.

    Having used it for a couple of days now... I have seen some things that have had me wondering if what Ive noticed are normal... or oddities to be concerned about.

    Firstly, when looking inside the machine (through the grill under the cup warmer) I can see the boiler. When I turn the machine on, and just before the unit gets to temperature, there is a pressure valve that splutters, spits and hisses quite a bit of water for about 5 seconds till it seals. It ends up that the water is being spat around inside the chassis and as a result some ends up on the electrical connections and wiring. Is this normal? *I would have thought this to be a design fault and that the valve would have been shrouded to prevent possible electrical problems.

    Secondly, can firm (perhaps over-firm) tamp pressure stop the shot from pouring?
    Tonight I thought I would experiment to see what would happen if I tamped a little more firmly than usual. Having loaded a freshly ground dose into the basket, I put 2 cups under the portafilter... the machine made its usual noises - but nothing came out!
    I stood there waiting for at least 25 - 30 seconds but literally only a couple of drops dripped out. I returned the lever to off position fearing damaging the machine.
    Is this normal?
    Can it harm the machine to have this happen?


    Thirdly, can someone direct me towards a manual or guide on machine use with respect to proper turn on and turn off procedures for these types of machines? In fact, a guide or list of procedures from go to whoa would be great as the Diadema manual is bloody useless.
    Im hearing things like "leave the steam-wand valve open when turned off to vent pressure out of boiler" and also "leave steam-wand valve open when first turned on in the morning, until the steam pressure builds and hisses out of steam wand".
    If this advice is correct can someone explain why these processes are important. Im the kind of fella who like to understand why something is so... *having never owned a high end machine I am pretty oblivious on how to use and treat them and would like to look after it in the best way possible. Utilising good practices from the start has to be the way to go - its just finding out what those practices are that Im finding interesting.

    Cheers for reading guys. I look forward to being able to make contributions to your forum.


  2. #2
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    Re: Questions on machine operation.

    auton0my,

    The valve which is spluttering water is the anti-vacuum valve..... designed to let air into the boiler when it cools down (to prevent a vacuum) and to let air out as it heats up so the boiler is full of steam - not air. Air provides false pressure and you wont be able to texture milk correctly if air is present.

    It will spit and sputter a little (it is cool.... steam condenses on it producing water which is blown out). I wouldnt expect the water to go onto the electrical connections - that is bad, bad, bad!!! *:o :-[

    The pump produces 9 bars (if correctly adjusted).... tamp too hard or use a fine grind and 9 bars cant penetrate it.... so no extraction - perfectly normal and wont harm the machine (it has an over pressure valve to protect it)

    The anti-vacuum valve mentioned above regularly fails on most machines and sticks closed...... (well at least you wouldnt get spluttering water if that happened)... However you can then get a vacuum (which can draw milk etc from the wand back into the boiler) and false pressure at start up. *That is why if you attend a commercial machine workshop (and you should!) you will be told to always open the steam wand at shut down and leave it open until a good head of steam is coming out when it is warming up.

    And also never - never ever, leave the wand soaking in a cleaning solution, milky water or anything else. This can get sucked into the boiler and contaminate the water...... :P :P

    All this - and more - will be explained if you attend a workshop...... *;)


  3. #3
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    Re: Questions on machine operation.

    Hi,

    Ive finally been able to afford to buy a new machine and bought myself a new machine (that would be described on the these CoffeeSnobs forums as "pointy end").
    Congratulations. *By skipping cheaper machines, you are probably on a much quicker and easier path to deliciousness. *Presuming that you also have a decent grinder ;P

    Firstly, when looking inside the machine (through the grill under the cup warmer) I can see the boiler. When I turn the machine on, and just before the unit gets to temperature, there is a pressure valve that splutters, spits and hisses quite a bit of water for about 5 seconds till it seals. It ends up that the water is being spat around inside the chassis and as a result some ends up on the electrical connections and wiring. Is this normal? *I would have thought this to be a design fault and that the valve would have been shrouded to prevent possible electrical problems.
    Sounds like you are describing the anti-vacuum valve. *The purpose of this valve is to prevent a vacuum forming when the machine is turned off and the steam cools. *I gather that this can stop the pressurestat from switching the heating element on. *The pressure of the steam in the boiler closes the valve and, conversely, it drops open when the machine cools. *Some manufacturers put a shroud around their anti vac valves; some do not. *It shouldnt cause a problem, but water on the electrical connections sounds bad - can you actually see that happening? *You can probably DIY with some heat shrink tubing if you want, but Ill leave you with the standard warning that if you fool around with your machine without knowing what you are doing, you might damage it, electrocute yourself or otherwise pry open pandoras box.

    Secondly, can firm (perhaps over-firm) tamp pressure stop the shot from pouring?
    Tonight I thought I would experiment to see what would happen if I tamped a little more firmly than usual. Having loaded a freshly ground dose into the basket, I put 2 cups under the portafilter... the machine made its usual noises - but nothing came out! *
    I stood there waiting for at least 25 - 30 seconds but literally only a couple of drops dripped out. I returned the lever to off position fearing damaging the machine. *
    Is this normal? *
    Can it harm the machine to have this happen?
    The tamp pressure has a relatively small impact on the flow rate of the resultant espresso, whereas the dose and grind have a huge impact. *If the dose and grind are right, even a really heavy tamp probably wont choke your machine. *Chances are that you overdosed without realising. *Most beginners to espresso totally underestimate how difficult it is to consistently dose the same amount of coffee and how much that can affect the resultant shot. *

    I very much doubt that the experience would have harmed your machine. *These things are designed to deal with stuff like that; backflushing your machine would put similar stress on it ... though I guess that a backflush wouldnt last as long.

    Thirdly, can someone direct me towards a manual or guide on machine use with respect to proper turn on and turn off procedures for these types of machines? In fact, a guide or list of procedures from go to whoa would be great as the Diadema manual is bloody useless.
    This is a concise overview of the whole process. *

    As for a specific turn on procedure; I dont think that theres anything too much to worry about. *Just make sure that you turn the machine on half an hour before you want to use it. *You can use an appliance timer, but remember that theres always a risk in having the machine switch itself on with no one around; for example, if the brew lever is engaged, it will pump all the water out of the tank and might burn the pump out in doing so, not to mention water flooding everywhere.

    Im hearing things like "leave the steam-wand valve open when turned off to vent pressure out of boiler" and also "leave steam-wand valve open when first turned on in the morning, until the steam pressure builds and hisses out of steam wand".
    If this advice is correct can someone explain why these processes are important.
    You dont need to do that; the anti-vac valve spluttering when your machine starts up is taking care of it for you.

    Hope that helps; if you have any more questions, keep them coming.

    Cheers,

    Luca

  4. #4
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    Re: Questions on machine operation.

    Thanks for your comments gents... very much appreciated. Those answers were almost in before I even submitted my questions. :)

    Ah, an anti- vacuum valve... that makes perfect sense. In fact, Im kind of embarrassed to have asked seeing now that the answer is so obvious.
    And yes, I have observed water sputtering down onto the cables and terminals below. I think this is a gross oversight from the manufacturer.
    Being a machinist I will get to making a stainless steel shroud and placing it around the valve this weekend. Im actually shaking my head in disbelief that they allow this to happen and that it passes safety regulations.

    As far as tamp pressure and the possibility of grind/dose problem: I did buy a decent grinder (Macap). Although it is doserless - it is electronic and grinds a precise amount each time. Im not certain, but Im fairly sure that it wasnt overdosed. But as you said, the grind may have been to fine.... definitely going to have to look into that.
    Thanks Luca for posting that link. Its going to be a slow day at work today so I will read that stuff thoroughly.

    As far as the differing answers relating to whether the steam-wand valve should be open or closed when turned off and turned on - Im not here to start a debate, so Ill just say thanks to you both for your answers. Differing answers always makes good food for thought.

    I like the advice on taking a "commercial machine workshop" - Im an information and knowledge whore... so Im always keen to learn new things (and refresh old and forgotten stuff) about subjects I am passionate about... Im going to have to get on the job of finding a course that I can attend that will give me a good grounding on the fundamentals.

    Cheers gents... I look forward to further interactions with you all.


  5. #5
    Senior Member ozscott's Avatar
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    Re: Questions on machine operation.

    Welcome matey. You have had the benefit of some very experienced snobs above. You will have to change the grind regularly...if the whether gets more or less humid will sometimes be enough. If you change beans...and as the beans age...its a living process.

    Also the way you dose - look at that. I dose move the grinds around a little with my little finger, knock the PF on the bench a few times, repeat and then dose level and tamp. Some people do it differently.

    Cheers

  6. #6
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    Re: Questions on machine operation.

    Quote Originally Posted by auton0my link=1225969821/0#3 date=1226009892

    As far as the differing answers relating to whether the steam-wand valve should be open or closed when turned off and turned on - Im not here to start a debate, so Ill just say thanks to you both for your answers. Differing answers always makes good food for thought.
    This is similar to the debate as to whether you leave a manual car parked on a hill in gear...... If the handbrake is maintained and adjusted correctly - it should hold the car..... but leaving it in gear will ensure it doesnt roll down the hill..... even if the handbrake fails.

    Anti-vac valves are notorious for getting stuck closed - especially on commercial machines which are left on for extended periods. They are typically a neoprene O ring which seats onto a surface to seal...... and they can adhere to that surface. When I rebuilt by LC I put a new kit through the anti-vac valve (as well as lots of other parts)..... and occasionally it sticks!

    So opening the steam wand is insurance against that happening - In theory it shouldnt be needed..... but just like leaving the car in gear.... only costs a couple of extra seconds and provides peace of mind!

    There are commercial machine workshops / training sessions run by many suppliers/retailers - including site sponsors - and also some independent bodies - I did mine at the WA Barista Acadamy here in WA (no site sponsors in WA). Courses generally cost a few hundred dollars (they are aimed at commercial use and therefore arent cheap) but are VERY worthwhile.

    Good luck on your journey.

  7. #7
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    Re: Questions on machine operation.

    Thanks for the reply Java.

    My personality type is one that lends itself to preventions are always better than cures... therefore I have been leaving the steam-wand valve open when I turn the machine off and also for 20 seconds or so after steam first starts coming out after startup.

    If nothing else, the last week has showed me that there is a lot to learn on this journey and Im certainly enjoying it so far...


  8. #8
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    Re: Questions on machine operation.

    If you are happy to open and close the steam wands when you start up and turn off the machine, then thats great. If youre lazy like I am, the consequence of not doing so is merely that if you turn the machine on, it might not heat up. You arent going to damage your machine either way and you arent going to prevent anything that would otherwise need a cure, youre just avoiding having to do it if the anti-vac fails. The anti-vac valve will function normally or get stuck closed regardless.

    I like to have my machine turned on by timer, the convenience of which is rendered irrelevant if I need to take a hike to my espresso machine before my morning shower. For what its worth, my anti-vac valve hasnt gotten stuck in the several years that I have had it and whilst I have no doubt that it happens, in something like eight or nine years working in cafes I havent personally run across a problem with an anti-vac valve sticking, nor have I heard anyone complain of such a thing.

    At the end of the day; its six of one and half a dozen of the other.

    Cheers,

    Luca

  9. #9
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    Re: Questions on machine operation.

    Dont know Luca...granted, if the machine is on a timer its a PITA to have the steam valve opened.

    I think if you had worked in repairs rather than in cafes, you might have seen enough machines with milk in the boiler to argue that it should be opened. ;)

  10. #10
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    Re: Questions on machine operation.

    Milk in the boiler is a different issue that is almost unrelated to this.

  11. #11
    Sleep is overrated Thundergod's Avatar
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    Re: Questions on machine operation.

    Behmor Brazen - $249 - Free Freight
    Quote Originally Posted by cuppacoffee link=1225969821/0#8 date=1226036618
    Dont know Luca...granted, if the machine is on a timer its a PITA to have the steam valve opened. *

    I think if you had worked in repairs rather than in cafes, you might have seen enough machines with milk in the boiler to argue that it should be opened. ;)
    If the wand is purged after steaming the milk then isnt impossible to suck milk into the boiler by leaving it on a timer?



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