Announcement

Collapse
No announcement yet.

Possible EM6910 temp problem

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Possible EM6910 temp problem

    Just bought a new 6910.
    Not completely happy with the pour which seems to come out a bit thin and blondes pretty early (crema seems OK though)
    Using non pressurised baskets
    Decided to check the temperature via the styrofoam cup method and K-type probe. I put some holes in the cup near the bottom to let only a small amount of hot water (5mm) pool on the bottom.
    Even with the 96 degree setting my maximum temp was 87 degrees, this after trying numerous methods of starting and stopping, waiting a number of seconds and starting again.
    I did a test of boiling a jug of water (check the probe in jug - OK 99-100 degrees) then pour the boiling water into my styrofoam cup setup and got readings of up to 96 degrees. Thought this was a good reading as the cup was open at the top and would loose heat as I poured.
    Is there an easy way of fixing this via a variable resistor on the board
    I know that I should ask Sunbeam service but am unsure if they would bother testing this accurately and just give me the usual "no it seems fine to us"
    I say this as I own a breville BES820 that had a low temp problem and the service guy told me it was OK. Had to fix this myself with an inline variable resistor with the thermistor.
    Any help would be appreciated
    :-[
    Thanks
    Todd

  • #2
    Re: Possible EM6910 temp problem

    Hi Shawty,

    I too own an em6910 and have done the styrofoam cup test with a thermocouple. I got lower readings than that. My thermocouple is reasonably accurate.

    I put it down to a flaw in my test method. while Im not so presumptuous as to declare my coffee better than some of Melbournes top cafes, my coffee tastes pretty good and doesnt have the soureness I would associate with a low brew temperature.

    If it really bothers you, I would try to further verify that your test method is accurate. At the end of the day, a cheap thermoblock is never going to be as stable as a pricey HX or dual boiler, but I think my beamer does a fair job for the price.

    As far as I know, no one here has tried to hack their 6910 to the extent youre talking about; but Im happy to be a spectator for you.

    -ACog

    Comment


    • #3
      Re: Possible EM6910 temp problem

      Originally posted by 564D4452515C250 link=1241125627/0#0 date=1241125627
      Just bought a new 6910.
      Not completely happy with the pour which seems to come out a bit thin and blondes pretty early (crema seems OK though)
      Using non pressurised baskets
      Decided to check the temperature via the styrofoam cup method and K-type probe. I put some holes in the cup near the bottom to let only a small amount of hot water (5mm) pool on the bottom.
      Even with the 96 degree setting my maximum temp was 87 degrees, this after trying numerous methods of starting and stopping, waiting a number of seconds and starting again.
      I did a test of boiling a jug of water (check the probe in jug - OK 99-100 degrees) then pour the boiling water into my styrofoam cup setup and got readings of up to 96 degrees. Thought this was a good reading as the cup was open at the top and would loose heat as I poured.
      Is there an easy way of fixing this via a variable resistor on the board
      I know that I should ask Sunbeam service but am unsure if they would bother testing this accurately and just give me the usual "no it seems fine to us"
      I say this as I own a breville BES820 that had a low temp problem and the service guy told me it was OK. Had to fix this myself with an inline variable resistor with the thermistor.
      Any help would be appreciated
      :-[
      Thanks
      Todd
      As per ACog..

      It is not as simple as it may appear and there are many variables that you have not covered..

      The temp is going to have some impact on the crema, but no where as much as the Quality of the beans and the grinder.. These factors and you tamping will have a significant impact on the flow and pour..

      Some time ago... 12- 18 months I did a detailed test and while not perfect was more than happy with the temp "IN THE PF BASKET".... I think I was getting around 90 at default plus one setting higher...

      Unless your Group head and basket is at a good stable temp (92 or there a bouts) any fulid passing through it will loose temp and when then falling through the air and hitting a cold cup it will also loose temp... Due to surface area and Ambient temp, this can all be quite considerable..

      Like many scientific processes; ASSUMPTIONS and or not considering all the variables leads you up the path...

      Step ONE:

      1: Fresh beans - NOT supermarket
      2: Good Grinder -
      3: Method - Tamp etc
      4: Consistancy..

      Last but not least the machine... In 99% of cases... The user is the cause of teh problems....

      And it can be just not knowing or understanding the equipment..


      Comment


      • #4
        Re: Possible EM6910 temp problem

        As above.

        We turn the machine on, pf and basket in place, and leave it for 20-30 minutes to get heat through all the metal. This has a huge factor on the brew temperature.

        It is not as simple as waiting for all the lights to come on and letting rip.

        Chris

        Comment


        • #5
          Re: Possible EM6910 temp problem

          Thanks for your replies
          I roast my own beans from beanbay, so I can assume they are fresh
          The styrofoam cup I have modified so that the water only has 50mm drop from shower screen to the bottom of the cup, so I dont think I would be dropping any more than a couple of degrees in measurement due to heat loss to the air inside the cup.
          Machine is left on at least 30mins before testing and then flushing a small amount of water through the group.
          Then test.........
          When pulling a shot:
          Beans not quite a week old (PNG Whagi AA)
          Grinder is the EM0480
          Do the 5 cent thing
          End up with shower screen impression on puck at end of shot
          Seem to have to updose the baskets a lot (above 7g single & 14g double) to have this happen.

          Comment


          • #6
            Re: Possible EM6910 temp problem

            shawty,

            Are you using a bead type thermocouple or the probe? If the probe, it may be losing some heat as I can imagine its not totally immersed in the water coming out of the group head. Thats where I think I went wrong. I think a bead type is better for this.

            Comment


            • #7
              Re: Possible EM6910 temp problem

              The bead type
              As I said I have tested it with boiling water poured into my setup on the bench - well sink - and got the results I thought that I would get allowing that the open pouring method would loose more heat than my actual testing method at the group head
              The only reason I am going down this line is just so that I can eliminate one of the variables as my problem.
              I have only been making espresso coffee for a couple of months so I know that I have a lot to learn and appreciate all the help that I can get
              I really dont even mind the taste at the moment its just that I like to fiddle around to get things right

              Comment


              • #8
                Re: Possible EM6910 temp problem

                Originally posted by 504B4254575A230 link=1241125627/4#4 date=1241139833
                Beans not quite a week old (PNG Whagi AA)
                Grinder is the EM0480
                Do the 5 cent thing
                End up with shower screen impression on puck at end of shot
                Seem to have to updose the baskets a lot (above 7g single & 14g double) to have this happen.
                Dump teh single :-)

                Ignore the term updose 4 the moment... If you get an impression, the the dose is OK.

                How fine a grind and what level of tamp... I tend to grind fine and tamp light.. But it does depend on teh beans and other things...

                Originally posted by 504B4254575A230 link=1241125627/6#6 date=1241142671
                The only reason I am going down this line is just so that I can eliminate one of the variables as my problem.
                I have only been making espresso coffee for a couple of months so I know that I have a lot to learn and appreciate all the help that I can get
                I really dont even mind the taste at the moment its just that I like to fiddle around to get things right
                I went and did a test and set my temp to LOW... A slight taste difference, but no noticeable change to the pour...

                I Will go and have a play (check Temps), but am still suggesting PEBKAC

                Hang in there it will come in time

                Comment


                • #9
                  Re: Possible EM6910 temp problem

                  Also as you are in Sydney, book yourself into the free Sunbeam course.

                  The better half did it and it helped heaps with our grind/dose/tamp equation and it is specific to that machine.

                  Our shots got a LOT darker and better following their lead.

                  Chris

                  Comment


                  • #10
                    Re: Possible EM6910 temp problem

                    Thank you all for your help in this
                    AM
                    Interesting that lower temp setting didnt change the pour much, will be interested to see what temp you think that it is set at
                    Tried finer/lighter and it seemed to thicken the pour a little although I had to use different beans
                    Sorry, what is "PEBKAC"?
                    CKSYD
                    Good idea, I am going to do the course for sure. Nothing like hands on help to point you in the right direction. Unfortunately it might be a while as I coach my sons soccer team, they play on Saturdays and the course is on Saturdays as well.

                    This coffee thing is harder than it looks but it is fun trying to figure it out ;D

                    Comment


                    • #11
                      Re: Possible EM6910 temp problem

                      Originally posted by 273C3523202D540 link=1241125627/9#9 date=1241166186
                      Thank you all for your help in this
                      AM
                      Interesting that lower temp setting didnt change the pour much, will be interested to see what temp you think that it is set at
                      Tried finer/lighter and it seemed to thicken the pour a little although I had to use different beans
                      Sorry, what is "PEBKAC"?
                      CKSYD
                      Good idea, I am going to do the course for sure. Nothing like hands on help to point you in the right direction. Unfortunately it might be a while as I coach my sons soccer team, they play on Saturdays and the course is on Saturdays as well.

                      This coffee thing is harder than it looks but it is fun trying to figure it out ;D

                      1:  See my post on about 2007   http://coffeesnobs.com.au/YaBB.pl?num=1175333065/130#130

                      2: Interesting that lower temp setting didnt change the pour much ?  

                      As I said... Slight change to the flavours... BUT not the pour its self..  And neither did I expect it to...

                      3: PEBKAC  Google is a friend  ;D

                      Originally posted by 273C3523202D540 link=1241125627/9#9 date=1241166186
                      This coffee thing is harder than it looks but it is fun trying to figure it out  
                      Not always fun    Sometimes you have to just accept the facts and what your seeing / getting... Trying to break it down to every minute step... Just causes pain to teh back of the eyes...


                      [edit]Update[/edit]

                      Just did a confirm here again... Oh I tired of this...

                      1: Almost the same temps obtained... Be aware it is tricky once the water flows.. You really should be measuring directly at the point of entry... Or up on top of the shower screen...

                      2: As I have an old EM6910 (Thanks FL - Need a lathe now ) I ran it up and it is not quite as good as mine..

                      Though I may not have given it enough time to warm up and it is in parts..

                      On looking... You could play with the insulation to the temp sensor and introduce a small error/offset... If it was bothering you..

                      Search for the pics I posted as to Changing the Group Head / collar and or Steam wand repair etc.. You can see the OT device and the sensor..

                      Comment


                      • #12
                        Re: Possible EM6910 temp problem

                        Ok..

                        Here are some pics and info as to the group collar http://coffeesnobs.com.au/YaBB.pl?num=1233294485

                        It may also assist you in understanding the guts of teh Em6910 without pulling it apart YET..


                        1:  Just confirmed at Ambient the thermistor is 100k

                        2: Yes it goes low as temp increases...

                        So...  With that in mind, if you wished to trick the 6910 to drive slightly higher... you would need to add some resistance in series

                        Uses a stand connector not unlike what is used for some of the small fans on many modern MOBs.

                        Thus a little work, could see a  interface lead with a fixed resistor OR adjustable one for testing...

                        NOTE 1:  I will check out the actual temp of teh thermoblock, but would suggest it will be close to the desired temp..   Trying to check the resistance when in CCT and system on is not  good for many reasons.  And it is sensitive enough that there is plenty of movement as soon as the heating is removed..  Not sure what band has been set for the ON / Off but that is teh reason why there is some mass.

                        In addition, as it is a thermoblock it has the potential to deliver different temps unless you FLUSH first...  When sitting any water can / will be at the block temp...  When pumping, then cold water is entering and hot water is leaving.. Thus there is some interesting thermodynamics taking place..

                        Further more if the block is set too high and you dont flush... YOU WILL BURN THE COFFEE...

                        NOTE 2:  Would suggest a  couple of degrees up at MOST, for many reasons....  

                        Remember if your  PF and Group is not at  92  (And they will not) and your measuring the temp in a cup... There will be a few Cs lost..  

                        Always err on teh side of safety, cause if you over drive the heating CCT you could always BLOW the system up...


                        UPDATE:

                        Block temp taken with teh shower screen off and inserted up and into the block- Not my A$#

                        Ambient 24C and the on surge to 100C at start up.

                        At approx 15min..

                        1: At default the temp is on average 93 C

                        2: At the next level 96 C

                        3: At the highest 98 C

                        As this was a static test... I can only assume that the Water, would be exiting at or about; 2 to 3 C below the block temp at worse case...

                        Which is exactly what you want...

                        Was going to Data log it all... But hey ... No one will believe me any way ;D

                        Think I might go and kick the musses and take teh cat for a jog / drive

                        Cop that speeling police :


                        Comment


                        • #13
                          Re: Possible EM6910 temp problem

                          AM
                          Great stats for me to work with especially:
                          1: At default the temp  is on average 93 C

                          2: At  the next level  96 C

                          3: At the highest 98 C

                          I should be able to see if mine is similar
                          I am assuming the bead the thermocouple is being poked up the hole in the thermoblock behind the showerscreen, then a small flush to have the bead surrounded by water, then rested to let the thermoblock & water temp stabilise.

                          Will try this and post results.

                          Uses a stand connector not unlike what is used for some of the small fans on many modern MOBs.
                          stand= standard?
                          MOBs ... are we talking motherboards here (sorry, I struggle with acronyms usually)
                          This is also probably the only way I would mod the thermistor, before it runs out of warranty anyway. If not exactly the same as a motherboard fan connector could you suggest a place to look for minature connectors. (in Sydney)

                          Remember if your  PF and Group is not at  92  (And they will not) and your measuring the temp in a cup... There will be a few Cs lost..  
                          At no stage have I tested water temp with the portafilter in, I assumed that it would take heat from the water and thus not make my test very accurate... well less accurate anyway!!!

                          By the way I checked my bes820 thermistor by getting the machine to temp, unpluged machine, then unpluged the thermistor & tested. A non-contact thermometer only had the thermoblock drop a few degrees during this process.

                          Thanks a lot for this info

                          Comment


                          • #14
                            Re: Possible EM6910 temp problem

                            Originally posted by 6E757C6A69641D0 link=1241125627/12#12 date=1241486436
                            I should be able to see if mine is similar
                            I am assuming the bead the thermocouple is being poked up the hole in the thermoblock behind the showerscreen, then a small flush to have the bead surrounded by water, then rested to let the thermoblock & water temp stabilise.

                            Will try this and post results.
                            I never bothered with the flush (Fishing Lizards - I will call him Flathead) machine is in such an UN save status.. Did not want water every where.... Damm lizards spike ya, if ya not carefull.

                            Originally posted by 6E757C6A69641D0 link=1241125627/12#12 date=1241486436
                            stand= standard?
                            MOBs ... are we talking motherboards here (sorry, I struggle with acronyms usually)
                            Yep Motherboard.. Not sure if you can buy them except maybe from Jcar.. However I have plenty of old fans ect (two pin) that the connector is the same..

                            Could provide at a cost ($1,600 - Need to fund my coffee addiction )

                            Originally posted by 6E757C6A69641D0 link=1241125627/12#12 date=1241486436
                            At no stage have I tested water temp with the portafilter in, I assumed that it would take heat from the water and thus not make my test very accurate... well less accurate anyway!!!
                            Now this is where many go wrong as teh DEVIL is in the detail and real Physics...

                            Once the water leaves the thermoblock and or Boiler it will loose temp, for many reasons. The rate is dependant upon many things as well.

                            At no stage are you going to get 90C or close to it, in teh cup. Unless the PF, group and ALL the packed coffee is at 92 - 93C to start with.

                            The moment it hits the coffee grounds, or leaves teh boiler it is cooling;

                            Then you have;
                            1: The spacial across the depth of teh puck...
                            2: The thermal transfer to teh PF
                            3: Then as it follows the spout the top surface is exposed to Ambient air temps
                            4: Then depending on teh flow rate and if it brakes up or has bubbles it again looses temp at a faster rate due to the thermal mass and dynamics involved.
                            5: Then there is teh effect of the cup and the mass and rate of transfer between teh surfaces etc..
                            6: Last but not least is the accuracy of the probe and its reaction time...

                            Now with OIL ( Coffee oil / extraction that is) it has a diferent thermal mass to water and if my understanding is correct, retains heat a little better.

                            When you do a test with water (NO PF or Not) then any splatter and or spray (not a solid stream) etc etc just compounds the rate of temp loss.

                            Further more if you have the heat the Boiler / block to a temp close to 100 or highter... You have but one outcome..

                            Scorched / Burnt beans...

                            However, that is my 2 cents worth... Well may be only 1 cent..

                            But the experiance and investigation process is such, that we can all learn

                            PS. I am sure that I have missed any number of other factors and some of teh HX and E61 system attempt to manage some of this.. However you have an EM 6910 :-[

                            Blonding etc will be the Beans, Grind and Tamp

                            PEBKAC ;D







                            Comment


                            • #15
                              Re: Possible EM6910 temp problem

                              Could provide at a cost ($1,600 - Need to fund my coffee addiction)
                              How many do I get for this... and is that including GST???

                              I think I would be happy if I know that my thermoblock is heating up to 92d on standard setting. I am only looking for the water to be around that temp as it leaves the shower screen at the start of the pour
                              I just think that at the moment I am about 10d below that scenario

                              Comment

                              Working...
                              X