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Thread: New HX machine - boiler pressure too high?

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    New HX machine - boiler pressure too high?

    Gday all
    I mentioned in my other thread about choosing a machine that I ended up going for an Isomac Mondiale. The local retailer said theyd calibrate it for me but made a comment that there was only limited adjustment that could be made on these machines.

    Anyway the guage for brew pressure went to 10 bar with almost no flow (ground too fine on that shot), otherwise sits around 9.5 bar. my research on the forum suggests that the machines guage will often read about 1 bar high, so until I get it properly measured, is it likely that its ok?

    I think the coffee tastes a bit thin and burnt though, although it might take more than a couple of days to get the hang of the new machine (used to use a sunbeam 6910).
    Im new to the world of cooling flushes, and I think I may not have been flushing long enough. I worked out just now that after sitting idle for about an hour, it takes about 20-25 seconds before it stops fizzing and spitting, but I was only running about 5 seconds or so through it. 20 seconds is a bit long though isnt it?

    The boiler pressure guage sits between 1.31 and 1.5 bar (mostly sits on the lower end of that) but reading some other threads suggests it should only be about 1.1 bar? Is that correct? can/should my machine be adjusted? will that adjustment affect the brew pressure?

    thanks
    Geoff

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    Re: New HX machine - boiler pressure too high?

    Quote Originally Posted by 7955554A5F480C03693A0 link=1256380339/0#0 date=1256380339
    Gday all
    I mentioned in my other thread about choosing a machine that I ended up going for an Isomac Mondiale. *The local retailer said theyd calibrate it for me but made a comment that there was only limited adjustment that could be made on these machines.

    Anyway the guage for brew pressure went to 10 bar with almost no flow (ground too fine on that shot), otherwise sits around 9.5 bar. *my research on the forum suggests that the machines guage will often read about 1 bar high, so until I get it properly measured, is it likely that its ok?

    I think the coffee tastes a bit thin and burnt though, although it might take more than a couple of days to get the hang of the new machine (used to use a sunbeam 6910).
    Im new to the world of cooling flushes, and I think I may not have been flushing long enough. *I worked out just now that after sitting idle for about an hour, it takes about 20-25 seconds before it stops fizzing and spitting, but I was only running about 5 seconds or so through it. *20 seconds is a bit long though isnt it?

    The boiler pressure guage sits between 1.31 and 1.5 bar (mostly sits on the lower end of that) but reading some other threads suggests it should only be about 1.1 bar? *Is that correct? *can/should my machine be adjusted? *will that adjustment affect the brew pressure?

    thanks
    Geoff
    So does this mean you got it from a non sponsor ?

    Yes the boiler does have a flow on effect but with out knowing how it was set-up/ calibrated, can not say much more. My first thoughts is that it may require a little more setting up; but not being an owner or user... Can not say..

    See here: http://coffeesnobs.com.au/YaBB.pl?num=1163234999/20#20



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    Re: New HX machine - boiler pressure too high?

    Hello Geoff,

    At 1.3 to 1.5 bar, your boiler pressure is way too high and the group temp is probably more like 98+ deg. If youre not getting thin, bitter and disappointing shots Id be very surprised.

    The pressurestat in your machine needs to be set to more like a max of 1.2 bar and Im surpised that the guy you purchased from hasnt delivered that. You can do it yourself, but you have paid for that in the machine price and your supplier might void your warranty if you open the machine up.

    Perhaps it might be a good idea to ask your vendor what (if anything) he actually does in a bench test? I suspect that it may simply consist of lifting the box onto the bench so that the purchaser doesnt have to bend over to pick it up... :-?

    To me, the OPV setting sounds fine and most likely, this is how the machine was shipped to your supplier. Sounds to me like he got a nice margin for simply lifting a carton... ::)

    Chris

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    Re: New HX machine - boiler pressure too high?

    I
    Quote Originally Posted by 4F60696B7C436F606F696B636B607A0E0 link=1256380339/1#1 date=1256394871
    So does this mean you got it from a non sponsor ?
    the joys of living in a regional area... If I still lived in Perth, theres no question that I would have bought a VBM or Giotto from a sponsor (in fact I almost did) but in the end the idea of sending the machine to Perth for service pushed my decision back to the local non-sponsor Isomac supplier.

    Chris thanks for the info. *Yes the shots are quite thin, bitter and disappointing - shots from my 6910 tasted better.

    they were slightly hesitant when I asked them about calibrating the group pressure (didnt think to ask about the boiler pressure at the time), so on the off chance that the supplier disputes the fact that the boiler should be adjusted down to 1.1 bar, is there a non-forum technical resource I could show them to back it up? *otherwise Ill have to point them to CS *;)
    hopefully theyll agree to adjust it though - I dont want to void my warranty but you dont buy a machine of this level and then just put up with poor shots...

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    Re: New HX machine - boiler pressure too high?

    Quote Originally Posted by 517D7D627760242B41120 link=1256380339/3#3 date=1256432193
    I
    Quote Originally Posted by 4F60696B7C436F606F696B636B607A0E0 link=1256380339/1#1 date=1256394871
    So does this mean you got it from a non sponsor ?
    the joys of living in a regional area... If I still lived in Perth, theres no question that I would have bought a VBM or Giotto from a sponsor (in fact I almost did) but in the end the idea of sending the machine to Perth for service pushed my decision back to the local non-sponsor Isomac supplier.

    Chris thanks for the info. *Yes the shots are quite thin, bitter and disappointing - shots from my 6910 tasted better.

    they were slightly hesitant when I asked them about calibrating the group pressure (didnt think to ask about the boiler pressure at the time), so on the off chance that the supplier disputes the fact that the boiler should be adjusted down to 1.1 bar, is there a non-forum technical resource I could show them to back it up? *otherwise Ill have to point them to CS *;)
    hopefully theyll agree to adjust it though - I dont want to void my warranty but you dont buy a machine of this level and then just put up with poor shots...
    You dont say where your now located ??

    And your right... Sometimes there is not a sponsor close by.... Howevre with the high end machines; if their set up correctly, there should be little if any after market service required.. Note: Should.. Not always possible or if like me LUCKY.

    I would follow up with the supplier as not unlike many cafes... They provide an unpack and over teh counter service; but may not be fully edumudicated ;D

    Hope it all work out for you..



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    Re: New HX machine - boiler pressure too high?

    Quote Originally Posted by 725E5E415443070862310 link=1256380339/0#0 date=1256380339
    it takes about 20-25 seconds before it stops fizzing and spitting
    Hi Geoff,

    Thats a LOT of fizzing! Dropping the boiler pressure will help a little, but I doubt it will substantially get rid of the fizzing. My advice is to ask your retailer about the fizzing and see whether they can address the problem rather than just one of the possible causes.

    charlie

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    Re: New HX machine - boiler pressure too high?

    Quote Originally Posted by 04313C3B0F133F36363535500 link=1256380339/2#2 date=1256405230
    Hello Geoff,

    At 1.3 to 1.5 bar, your boiler pressure is way too high and the group temp is probably more like 98+ deg. If youre not getting thin, bitter and disappointing shots Id be very surprised.

    The pressurestat in your machine needs to be set to more like a max of 1.2 bar and Im surpised that the guy you purchased from hasnt delivered that. You can do it yourself, but you have paid for that in the machine price and your supplier might void your warranty if you open the machine up.

    Perhaps it might be a good idea to ask your vendor what (if anything) he actually does in a bench test? I suspect that it may simply consist of lifting the box onto the bench so that the purchaser doesnt have to bend over to pick it up... *:-?

    To me, the OPV setting sounds fine and most likely, this is how the machine was shipped to your supplier. Sounds to me like he got a nice margin for simply lifting a carton... ::)

    Chris
    Fair comments!

    Cheers,
    Luca

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    Re: New HX machine - boiler pressure too high?

    I spoke to the retailer, who gave me a number for the distributors technician. he talked me through dropping the boiler pressure - very easy job - but warned that my steam pressure would suffer.
    ive dropped it to max 1.3 bar and the cooling flush required has shortened a little. *it still needs about 10 seconds flush between consecutive shots. *i think ill need to get something to measure the temp so I know what its actually running at.
    also it now takes me over a minute to steam 300ml of cold milk to 60 deg C. is there a way to get the temp to behave more nicely without killing the steam power? i think i might need someone to set it up properly. should have trusted my instinct that buying off a sponsor would be a better experience.

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    Re: New HX machine - boiler pressure too high?

    Quote Originally Posted by 6C40405F4A5D19167C2F0 link=1256380339/7#7 date=1256792270
    I spoke to the retailer, who gave me a number for the distributors technician. he talked me through dropping the boiler pressure - very easy job - but warned that my steam pressure would suffer.
    ive dropped it to max 1.3 bar and the cooling flush required has shortened a little. *it still needs about 10 seconds flush between consecutive shots. *i think ill need to get something to measure the temp so I know what its actually running at.
    also it now takes me over a minute to steam 300ml of cold milk to 60 deg C. is there a way to get the temp to behave more nicely without killing the steam power? i think i might need someone to set it up properly. should have trusted my instinct that buying off a sponsor would be a better experience.

    Hindsite is a great thing but frustrating as it only ever comes after the fact.

    Now forsight would be good... But lining the two up is not so easy...

    Greg W has his item moving around for a small cost... Suggest you follow up.

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    Re: New HX machine - boiler pressure too high?


    Hi Cooper

    To begin with, you shouldnt need a 10 sec cooling flush between shots, and 1.3 is still too high a setting.

    A minute to bring milk up to temp isnt right and Gregs group gauge is not the answer at this point in time.

    Making one adjustment eg. pressure stat., can lead to the need to make adjustments to other components eg., opv. Without the right gear making changes can be hit and miss.

    Im sorry to say that I think you need to take it back to the retailer and put the onus on them to make it good.

    All the best!




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    Re: New HX machine - boiler pressure too high?

    I have to go with Cuppacoffee--it is a warranty issue and needs to be sorted.

    Just to give you a rough baseline--my machine tops out at 1.1 bar and takes about 8 seconds to steam 100 ml of milk. My standard cooling shot is about 30 ml of water and only when the machine has been idling for half an hour or more. Consecutive shots need no flush and even after idling, a no-flush shot tastes good.

    Greg

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    Re: New HX machine - boiler pressure too high?

    I suppose my main question at this point is this - is it likely that theres there anything technically wrong with my machine?

    I suspect that the retailer could just say that its set up the way its supposed to be and that Im requesting a non-standard configuration that theyre under no obligation to provide.

    I think that the services the sponsors offer in calibrating the machine before delivery to perform at its best are above and beyond what can be considered their obligation. If that is the case, Ill probably be expected to pay for the services of a "custom tune" on my machine. luckily I got the machine for a very good price, so if I have to pay for it to be tuned up, thats ok.

    Ill just need be clear in explaining precisely what I want them to do (in the correct terms) - or they might get the impression I have no clue what Im talking about and tell me theres nothing wrong with it. If anyone can advise precisely what I should be asking them to do that would be appreciated.
    thanks
    Geoff

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    Re: New HX machine - boiler pressure too high?

    a bit of an update...
    After speaking to a couple of other owners and retailers of these machines, it seems I was correct in that there is nothing wrong with my machine, so theres no use demanding that the retailer do warranty repairs to it.
    Apparently these machines are known to run a bit hot, one theory I was given being that they are designed for commercial constant-use environments.

    The tweaking the sponsors provide could probably resolve at least some of the issues. As far as Im aware, the Mondiale doesnt come with a thermosyphon restrictor, which may be one reason for the higher temp??? if this information is incorrect please let me know (also for the benefit of anyone reading this thread...)

    as for the retailer helping to modify the machine to be more temp stable in my very non-commercial environment, I had little joy with their technician.

    If I have to live with long cooling flushes, thats ok. I ended up winding the boiler pressure back to its original setting and steam performance didnt change that much - I think I wasnt measuring accurately when I said before it took over a minute to do 300ml, so Ill try winding it back down again later and test again. In response to Gregs post, I tried steaming 100ml of milk (in the wrong size jug - I dont have one small enough to do it properly) and it took roughly 12 seconds. I usually steam about 250ml in about 35 seconds which I suppose is still ok even if its a fair way short of class-leading.
    The one issue I need to resolve before Ill start feeling comfortable with the Mondiale is the temperature - in that I have no real idea what its running at.

    Five Senses Coffee - a roaster in Rockingham - sells Isomacs and has a Scace that theyre happy to test my machine with if I take it up there next week.
    They can work with boiler and group pressure and at least then Ill have a better idea of its temperature without it being a vague guess every time.

    Failing that making a big difference, Im seriously considering packing up my machine and shipping it east for some modding if that will come with a reasonable guarantee of having a machine thats nicer to live with.

    Geoff

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    Re: New HX machine - boiler pressure too high?

    Quote Originally Posted by 4864647B6E793D32580B0 link=1256380339/12#12 date=1260788861
    I usually steam about 250ml in about 35 seconds which I suppose is still ok even if its a fair way short of class-leading.
    That is seriously slow going Geoff for a machine of this class. Should be capable of texturing this volume of milk in less than 15 seconds....

    Quote Originally Posted by 4864647B6E793D32580B0 link=1256380339/12#12 date=1260788861
    a roaster in Rockingham - sells Isomacs and has a Scace that theyre happy to test my machine with if I take it up there next week.
    This would be seriously worth doing and should enable any functional problems to be identified and fixed - Providing their Tech(s) know what theyre about of course...

    Quote Originally Posted by 4864647B6E793D32580B0 link=1256380339/12#12 date=1260788861
    Failing that making a big difference, Im seriously considering packing up my machine and shipping it east for some modding if that will come with a reasonable guarantee of having a machine thats nicer to live with. *
    Dont think this will be necessary Geoff. If the roaster referred to above can not improve things for you then the original vendor has the obligation to get things running satisfactorily for you. Its not your fault that they may be espresso machine klutzes.... Stick to your guns mate and make sure they stand behind the product.... >:(

    Mal.

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    Re: New HX machine - boiler pressure too high?

    Hi Geoff,

    One of the big problems with the coffee internet is that we cant taste whats on the other end. I think that it would be irresponsible of us to encourage you to spend lots of time and effort getting your machine modified if you havent really done your homework to eliminate all of the other possible causes. I dont want to sound patronising, but I think that its worth running down a checklist to see if we can save you some money. The first question in the checklist is always if your coffee is any good. Next, is your dosing up to scratch? Most of the time when I ask this people say that they are great, but if you watch them pull shots there are actually subtle variations inbetween them that influence cup quality and have the potential to make things like temperature adjustment moot. The test that I like is to pull five shots back to back. Stop them at the same volume and measure the time. You pass if all of the shots are within, say, a three second window. I suppose that the next question for you would be if the grinder is up to snuff. If thats the problem, your money would probably be much better spent towards fixing that.

    Unfortunately, it is entirely possible that your machine doesnt have any restrictors in the group head. You could pull the plumbing apart to find out, but then be prepared to damage your machine and possibly yourself. If you are comfortable adjusting your machines pressure, you could try doing that, though, again, any tinkering inside your machine comes at the risk of possible damage to yourself and the machine. If you want to do this, at the very least make sure that the machine is unplugged. Not off; unplugged. Maybe drop it so far down that it tops out at 0.9 bar, let the machine idle there for a while and see if that gets you the result you are looking for from your espresso. If it does, then thats good evidence that brew temperature is actually the problem and that having someone tinker with your machine is not money down the drain. If it doesnt, then it suggests that brew temperature might not be the problem.

    The horrible thing about the whole situation is that restrictors tend to be simply teflon disks with a hole drilled in them. Cost to install appropriate restrictors at factory: $0.50, maybe. Cost to you to get appropriate restrictors installed: $hundreds! This is the sort of scenario that has plagued consumers in the US of A for quite a while, but, fortunately, seems to have been corrected a lot in Australia.

    Hope that helps,
    Luca

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    Re: New HX machine - boiler pressure too high?

    In all honesty,

    I dont think it is good advice to suggest that an owner of a new machine should start disassembling a machine while it may be still under warranty. While a Scace check and minimal adjustment remains in the province of "tuning" per se, disassembling components is a whole different kettle of fish and NOT to be recommended of someone without the requisite knowledge or at least equivalent mechanical knowledge....

    If the machine is still under warranty, such invasive incursions will no doubt void same.

    Mal.

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    Re: New HX machine - boiler pressure too high?

    Quote Originally Posted by 775A5E525F330 link=1256380339/13#13 date=1260794606
    That is seriously slow going Geoff for a machine of this class. Should be capable of texturing this volume of milk in less than 15 seconds....
    to clarify - that was 250ml of cold milk that I did - about 400ml steamed. *I still think it could do better. *can a steam tip change help? *boiler pressure sits around 1.1-1.2 bar while steaming and never drops...

    Quote Originally Posted by 775A5E525F330 link=1256380339/13#13 date=1260794606
    This would be seriously worth doing and should enable any functional problems to be identified and fixed - Providing their Tech(s) know what theyre about of course...
    Ive arranged to take the machine there on Monday, so hopefully the scace testing will answer some questions for me

    Quote Originally Posted by 5F465052330 link=1256380339/14#14 date=1260795158
    You pass if all of the shots are within, say, a three second window.I suppose that the next question for you would be if the grinder is up to snuff.If thats the problem, your money would probably be much better spent towards fixing that.
    Thanks Luca. *I do certainly understand your point, and I do probably need to upspec my grinder (a better - probably doser - grinder should be on the cards soon), and fine tuning my dosing technique could certainly improve the taste of the coffee.

    Unfortunately, if my machine is running too hot now, none of those things are going to change that, and the quality of the end-product will still be lacking. *What Im hoping to achieve with the scace testing is to get my pressure set as best it can be, and to see what length of cooling flush is required to bring it back to optimum temp after idling for a while.

    I had a play tonight with the foam-cup and milk thermometer style temp measurement - not sure if I did it correctly - the pics should show if I did... *
    with the boiler pressure running 1.1-1.3, I let it warm up for about 35-40 minutes, then tested it with a cut-down foam cup over the shower screen. *the thermometer temp shot up to 98 deg and dropped to about 91 after about 25 seconds of flushing. *continuing for an extra 10 seconds or so, it stayed around 91 deg. *I let it sit idle for 5 minutes and repeated the process with the same results. *up to 98 deg, then down to 91 deg after 25 seconds.

    Then I upped the pressure to where it was before - 1.3-1.5 bar and got these results.
    30 seconds after starting the flush - still at 98 deg:



    55 seconds after starting the flush - down to 95:



    65 seconds after starting the flush - down to 90 deg and it didnt drop any further than that:



    Anyway I probably shouldnt get too carried away until its tested properly with the proper gear.

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    Re: New HX machine - boiler pressure too high?

    Quote Originally Posted by 5A7676697C6B2F204A190 link=1256380339/16#16 date=1260965854
    to clarify - that was 250ml of cold milk that I did - about 400ml steamed. *I still think it could do better. *can a steam tip change help? *boiler pressure sits around 1.1-1.2 bar while steaming and never drops...
    Yes, I was referring to a 250ml milk volume, not the volume of the jug being used....

    Quote Originally Posted by 5A7676697C6B2F204A190 link=1256380339/16#16 date=1260965854
    Ive arranged to take the machine there on Monday, so hopefully the scace testing will answer some questions for me
    Excellent. Hopefully that will set your mind at rest with regard to the machines setup....

    Quote Originally Posted by 5A7676697C6B2F204A190 link=1256380339/16#16 date=1260965854
    Then I upped the pressure to where it was before - 1.3-1.5 bar and got these results.
    Boiler pressure setting affects the Steaming Capacity more than that of the Group. I would raise the issue of the need for high flush volumes when you drop the machine in for its Scace test. It is possible that a thermosyphon restrictor (gicleur) has been omitted during the machines assembly at the factory and would be a simple measure for their Tech(s) to check it out while its sitting on the bench.

    Quote Originally Posted by 5A7676697C6B2F204A190 link=1256380339/16#16 date=1260965854
    Anyway I probably shouldnt get too carried away until its tested properly with the proper gear.
    Agree ;)....

    Mal.

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    Re: New HX machine - boiler pressure too high?

    Hi Geoff,

    The behaviour of your machine sounds bizarre to say the least. I have only ever used the Mondiale once to train a client but I dont recall anything like that.

    I am surprised that there is no thermosiphon restriction employed, because I dont recall massive cooling flushes in the one I used. Id want to compare your machine with their demo model if I was you and all I can say is that if this is indicative of the machine in general, it points either to lousy QC, poor HX design or a lemon. If their techies reckon theres "nothing wrong" with the machine, one has to wonder if theyre all like yours?? *:o

    My instinct is that thermosiphon restriction is employed in the Mondiale, but not installed in your machine or that you have defective restrictors or the wrong gicleur.

    The use of the scace will be really helpful..

    Things that you want to achieve:[*]circa 92-94 deg at the group, verified by the Scace[*]circa 9 bar at the group, verified by porta-filter pressure gauge or Scace II[*]approx 1.2 bar at the boiler, whilst maintaining the above.

    I am pretty sure, that I can suggest some fixes over the phone which will get you near enough. I can also advise on how to check if a restrictor is installed in your machine as well as the gicleur.

    The thermostability upgrade we developed with Prof. Pete on the Giotto Premium allows for better settings than those above- *which is how we were able to soup it up. Nevertheless, if you can lock into something close to my suggested settings, you will have a much happier machine.

    regards

    Chris

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    Re: New HX machine - boiler pressure too high?

    I would be a bit wary of your measuring device, those milk thermometers are not super accurate.

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    Re: New HX machine - boiler pressure too high?

    Quote Originally Posted by 323C313E293F3E500 link=1256380339/19#19 date=1261170478
    I would be a bit wary of your measuring device, those milk thermometers are not super accurate.
    On that point, stick it in a pan of simmering water and check it out. It should of course read 100C adjusted for your barometric pressure. ;)

    If its accurate, Id say the machine is running hot, but somehow only when idling :-?. This will need someone who is familiar with the innards.

    Greg

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    Re: New HX machine - boiler pressure too high?

    Quote Originally Posted by 7B757877607677190 link=1256380339/19#19 date=1261170478
    I would be a bit wary of your measuring device, those milk thermometers are not super accurate.
    yeah - I understand that even if the thermometer is reading correctly, its not the most scientific way of testing the temperature.
    I verified that the thermometer accurate at 100*C by putting it in a saucepan of water boiling on the stove, but the accuracy below that temp hasnt been tested - I was really just playing trying to get some idea where its at because I was getting impatient having to wait until Monday to test it properly. Ill have a better idea of the real temp then.

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    Re: New HX machine - boiler pressure too high?

    Excellent, I have just had a couple of examples of when people have been using "recently calibrated" thermometers which were out by 15 degrees. :o Didnt make for great coffee.

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    Re: New HX machine - boiler pressure too high?

    Hi Cooper,

    Curious to know how you went with your hot running Mondiale....Any success in settling it down?

    regards

    Chris

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    Re: New HX machine - boiler pressure too high?

    Quote Originally Posted by 02373A3D09153930303333560 link=1256380339/23#23 date=1262857453
    Hi Cooper,

    Curious to know how you went with your hot running Mondiale....Any success in settling it down?

    regards

    Chris
    Gday Chris
    jurys still out im afraid. *Im thinking of getting one of Erics TC devices sent over from the US so I can keep a closer eye on it.
    After installing a restrictor ~2.8mm I thought it was fixed, but in reality I think it just takes much longer to warm up. * If I wait half hour to 45 mins after turning on, it barely needs a flush. *after a couple of hours idling, it seems to need just as much flushing as it did before I installed the restrictor. *then after flushing it doesnt heat back up quite as quickly as it used to, but it still needs a bit of a flush between shots (Im not very quick but that time also includes steaming the milk for the first shots). *

    As it stands, the flushing does seem to be reduced overall, and with a way to monitor the temperature Ill probably be quite happy with it how it is. *Erics TC seems to be the neatest option for doing that from what Ive found so far...

    maybe if I install a restrictor with a smaller orifice (2mm or 2.5mm??) it might maintain temperature better once fully warmed up, but could that mean it will be taking up to an hour after turning on before I can start making coffee??

    due to the long warm up times, the machine is usually on all the time except for while Im at work or asleep - turns on by a timer about 45mins before I get up in the morning... *Do most people leave machines running all the time like this or turn them off when not in use? *I only use it a few times a day, but dont like the idea of waiting an hour after I get the urge for a coffee...

    Im getting good tasting results out of it lately anyway which is great. *My wife has noticed an improvement since I modified it, which is good since she was a bit concerned when it was all apart on the kitchen bench that it might never work properly again. *no faith in me *::)

    one other thing - after installing the restrictor the machine seems to sound different. It makes sense to me that the restrictor would increase load on the pump - is this likely to be a problem??

    oh and in case you or anyone else wonders what the Cooper69S is all about, when I originally joined the forum, my toy was a 1969 Mini Cooper S. *Awesome car, should never have sold it but thats another story. *One day Ill change my username so that I stop reminding myself about it...

    thanks for the assistance in choosing a better grinder, hopefully it will turn up here in the next few days

    Geoff

  26. #26
    TC
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    Re: New HX machine - boiler pressure too high?

    Hi Geoff,

    2.8 is big- you may get better results out of 2 or 2.5....You really do need to play with a Scace to see what its up to. You may also need to experiment with pressurestat settings and different gicleurs as well.

    I have been using my Scace with Andys roast monitor software. Real time curves! *8-) [smiley=thumbup.gif]

    The heat up is concerning though.... :-/

    I have very little experience with this machine but it really sounds like it could be a case of dumb HX design to me. If the HX is too fat and too short, doesnt matter a whole heap what you do...

    Sadly, its pretty much impossible to create smart design from dumb :(

    Chris

  27. #27
    Mal Dimal's Avatar
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    Re: New HX machine - boiler pressure too high?

    Could even come back to Boiler Water Level or HX Mixing too.... :-?

    If this is not right it will alter the characteristics of the actual Heat Exchange to the Brew Water, to the extent that it wont matter what you do any where else in the hydraulic circuit ultimately the Brew Water is going to reach the same temperature as always (give or take) and require the same volume of a cooling flush.

    Personally, Id take it to someone like Chris who has all the test gear on hand combined with the knowledge gathered over many years to properly assess what is going on. It is really very difficult to try and determine the root cause of this sort of a problem via remote control unfortunately.... :(

    Dont know if any other sand-groper CSers can recommend someone to you....

    Mal.

  28. #28
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    Re: New HX machine - boiler pressure too high?

    Hadnt noticed this thread before due to being away ...

    Ive had a Mondiale for a couple of years and now getting what
    I think are very good results from it.

    At first though I did think it was running a bit hot and giving a
    longer cooling flush than expected. It was also adjusted to an
    excessively high brew pressure (13+ on the gauge).

    But since a couple of adjustments its working well. First was
    pressurestat, adjusted down to a 1.1 - 1.3 range. Then the
    brew pressure. It took a while to get around to doing this as
    it required pulling the cover off, but turned out to be
    pretty straightforward (I posted about that a few months ago).
    That is now set to just over 10 on the gauge.

    With this, cooling flush is 10 - 12 seconds when hot, and very
    short pulling consecutive shots (which I dont do very often so
    havent measured it). Warmup time is about 45 minutes but
    could I think get away with less.

    The technicians in the workshop of the Isomac distributor gave
    helpful advice on a couple of occasions about the workings of
    the machine and what I could expect to find when adjusting
    the OPV. Saved me a fair bit of fiddling around.

    I did for a while consider looking into restrictor mods etc but
    reached the conclusion that such mods can affect other aspects
    of thermosyphon operation and without knowing more about its
    specific design possibly difficult to get right.

    Nonetheless I think the evidence is a bit thin to categorize it as a
    dumb HX design ... :) Would be interesting to run some tests though.

    FWIW a while ago I attempted some temp measurements by poking a
    calibrated TC lead into a group handle stuffed with foil and locked
    into the machine (this can damage the TC wire but I took the risk).
    IIRC this stabilized in the 91 to 93C region after the flush.

    Anyway Im now pulling shots in the 30 second range with good
    crema and most importantly showing the origin characteristics
    that Id been hoping for, and consistent with what I get cupping
    the same beans.



  29. #29
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    Re: New HX machine - boiler pressure too high?

    this is very interesting...
    I arrived at the conclusion that my machine was behaving as it was designed to, based largely on it seeming to have the same temperature characteristics as many HX machines in the USA that Ive read about on the HB forums. Considering that many of the machines that are talked about on here as behaving very nicely are apparently modified on request by certain Australian distributors, Ive assumed that mine is an unmodified machine and I need to tweak it so that it plays nice...

    I found another thread a while ago from another Mondiale owner who seemed rapt with his machine, so sent a PM but he doesnt appear to have been active on the forum for a while and I havent heard back... other than that Ive been able to find out very little about other peoples Mondiales.

    dumb HX design is something that would be pretty difficult to fix, but now Im thinking that if other Mondiales only require a 10 second cooling flush when hot, then why is mine different?? The scace test seemed to verify that with the boiler pressure at 1.1-1.3 bar, my machine was running 94-95C after about 30 to 35 seconds flush and seemed to stabilise on that temperature.
    now after installing a (slightly big) restrictor it seems a lot better, but if other people are finding that their unmodified machines are behaving better than mine, maybe something is still amiss??

    Quote Originally Posted by 28213A2225212E400 link=1256380339/27#27 date=1263016886
    I did for a while consider looking into restrictor mods etc but
    reached the conclusion that such mods can affect other aspects
    of thermosyphon operation and without knowing more about its
    specific design possibly difficult to get right.
    Hazbean do you know if your machine has any restrictor installed?
    also how do you find the steaming performance? from some of the numbers I mentioned above, Im told mines a tad slow.

    Quote Originally Posted by 04292D212C400 link=1256380339/26#26 date=1262868481
    Could even come back to Boiler Water Level
    this isnt something Ive considered before... how might it affect things??
    thanks

    Geoff

  30. #30
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    Re: New HX machine - boiler pressure too high?

    Quote Originally Posted by 5164696E5A466A63636060050 link=1256380339/25#25 date=1262861353
    If the HX is too fat and too short
    here it is
    In...


    where the restrictor has been installed... size of the hole in the fitting at the end of the pipe was 8mm, and as I mentioned above, it now contains a restrictor at about 2.8mm


    Out...


    Out again...



  31. #31
    Mal Dimal's Avatar
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    Re: New HX machine - boiler pressure too high?

    Wow!

    That HX sits high in the Boiler. Doubt it is immersed in water at all so must rely totally on transference via Steam. Such being the case, water level wont make much (if any) difference. Still reckon you need to find a reputable, highly regarded technician in your locale to suss everything out properly and adjust/rectify what ever needs doing.... :)

    Mal.

  32. #32
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    Re: New HX machine - boiler pressure too high?

    Quote Originally Posted by 25080C000D610 link=1256380339/30#30 date=1263050488
    Still reckon you need to find a reputable, highly regarded technician in your locale to suss everything out properly and adjust/rectify what ever needs doing....
    Theres no-one in my direct area who can help, but I would have thought there should be someone in Perth who can offer the kind of services that the east coast people enjoy - someone knowedgeable enough to have a look and pinpoint where this machine could be improved. The guys at Five Senses sell Isomacs and could help with things like scace testing, but it seems they havent done any basic customisation of the HX machines to improve their performance.
    They seem more into major customisation - theres a blog on their website detailing their custom Mondiale. It is now a PIDd dual boiler machine with a Synesso Cyncra group. That seems like the perfect solution, but when I spoke to them they estimated at somewhere around $3k to modify a standard Mondiale they way theyve done it. They said theyve got a waiting list of people who are interested in having it done to their machines if they decide to offer it.
    so as it stands I might do a ring-around to see if I can find anyone, otherwise if I start with a temperature monitoring device of some sort I can probably live with the machine as it is. The coffee is very good, and the steam performance is ok. Ive thought about buying another steam tip and seeing how it goes with the holes drilled out a bit bigger. if it doesnt work then Ill just put the original one back on...

  33. #33
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    Re: New HX machine - boiler pressure too high?

    "Hazbean do you know if your machine has any restrictor installed?
    also how do you find the steaming performance?"

    I dont know if there is a restrictor -- as far as I know the machine is as
    supplied by the distributor. Ill find out when I get it serviced.

    We dont have much need for steaming any more, so dont use it very
    often. When we first got the machine, the steam pressure was
    overwhelming for our small amounts so my wife fashioned a couple
    of "cotter pins" from ss jewellers wire and stuck them into the two
    holes of the steam wand as a restrictor. Yesterday as a test I
    took 250ml of cold water at 5C and "textured" it (nice whirlpool
    anyway) stopping at 65C (measured with my TC). This took
    50 seconds. Would have been a lot less without the pins, will
    do another test without them when I can.

    Can the distributor offer any suggestions for service?

  34. #34
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    Re: New HX machine - boiler pressure too high?

    had a significant "penny drop" this week. I believe the reason that the cooling flush was greatly reduced the day I installed the restrictor was my air conditioning. hadnt really paid enough attention before to when it did or didnt require a longer flush, I was just confused as to why it sometimes seemed to require no flush, and other times needed the same length flush as it did before installing the restrictor. Its no wonder I had trouble getting consistent results...

    I received my digital thermometer from Eric Svendson this week. I noticed that when the air-con is on (in the evenings after work), the group head temp never gets much above 91*C, while in the mornings (and any other time the a/c is off)its up to 99*C within about 45 minutes after startup.
    Im now wondering if a 91*C group temp is too cool. is it?

    Im still working out how to use the thermometer properly - since it supposedly reads a few deg higher than the puck temp - need to experiment a bit more to work out how the different temps it reports relate to taste...

    Geoff

  35. #35
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    Re: New HX machine - boiler pressure too high?

    Do you have pics?

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