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Upgraditis: 2-group Grimac Commercial

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  • #16
    Re: Upgraditis: 2-group Grimac Commercial

    Originally posted by Sparky link=1173088713/0#14 date=1173145012
    Good one Robusto. A 5l boiler sounds nice and compact for home use. As someone who has just about come out of descale/clean rebuild process (I didnt type nightmare), Id thoroughly suggest a major rebuild.
    And a 5l boiler will be a lot easier to clean than my 17l tank engine boiler was ...... a rebuild is definitely worth it in the end.

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    • #17
      Re: Upgraditis: 2-group Grimac Commercial

      It looks like a sweet machine. Grimac uses the E61-type group, but the auto-dosing variant wont have any pre-infusion.

      The one concern with Grimac machies is that Coffeeparts doesnt stock parts, which is a bummer in terms of convenience.

      Maybe we should start a new club for people with 2 gr commercials?... 8-)

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      • #18
        Re: Upgraditis: 2-group Grimac Commercial

        Originally posted by Sparky link=1173088713/15#16 date=1173153845
        The one concern with Grimac machies is that Coffeeparts doesnt stock parts, which is a bummer in terms of convenience.
        As I said in my post in the Coffee Machines list - try to get a second hand commercial for which CoffeeParts has spares.... their range, service and price are all great..... as is their technical assistance.

        Maybe we should start a new club for people with 2 gr commercials?... 8-)
        Yep, there are a few of us around now.....

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        • #19
          Re: Upgraditis: 2-group Grimac Commercial

          Thanks again everyone: Heres an update.

          Grinders, in fairfield, Melbourne, contrary to rumours does stock, service and carry parts for all Grimacs. Thats where I went.

          I bought replacement group seals (only $2 each) and a new glass tube showing min/max plus a couple of grommets for where it slides into compressions nuts.

          All up, $48. Not bad so far.

          I descaled the boiler and heat exchangers with hot water and citric acid, forced through the heat exchangers and groups with a little sprayer. The water came out yellowish, which was a good sign the operation was working -- I hope that is what it means.

          Flushed clean water through boiler and heat exhangers.

          I removed and throughly cleaned and descaled some pipes, but not all.

          Reassembed everything, one small leak where Id forgotten to tighten a nut.

          This is where things go sour.

          Boiler pressure shows 1.1 bars. But there is no movement for the heat exhanger pointer, which remains at 2.2 bars.

          The left group volumetric buttons when pressed make all the right pump noises, but no water emerges.

          At first, water did come out of the right group, but now, nothing.

          Any suggestions? Is there any bleeding of the exchangers to be done?

          I havent removed the old group seals or removed and cleaned the shower screens yet.

          Could they be the problem? Perhaps lose scale in the works?

          Advice greatly appreciated.

          --Robustp

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          • #20
            Re: Upgraditis: 2-group Grimac Commercial

            Cancel that!!

            Ive realised that one thing I havent, quite rightly, touched, is the electricals. I just went back and made sure all the ribbon cables and connectors were pushed well into one of black boxes". Well, they were lose. Perhaps that happened accidently when I was bolting and unbolting things to the boiler and groups.

            In any case....both groups are now producing water.

            So Ill keep flushing water through to get rid of all the scale and citric acid residue.

            Tomorrow, when things are cool, Ill attack the group seals.

            --Robusto

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            • #21
              Re: Upgraditis: 2-group Grimac Commercial

              Robusto

              Ah, sounds like good progress being made.... and all is more or less working (certainly the expensive bits appear to be OK ).

              Not too sure of your descaling regime though...... You really need to strip the boiler down or you can end up with bits of scale which come off - dislodged by the citric acid - but not totally dissolved.... and these float about until they find some nice place to come to rest..... and that nice place will generally block up some important valve, pipe, jet etc.....

              You might be lucky..... I hope you are. :-/

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              • #22
                Re: Upgraditis: 2-group Grimac Commercial

                Originally posted by robusto link=1173088713/15#18 date=1173163257


                Boiler pressure shows 1.1 bars. But there is no movement for the heat exhanger pointer, which remains at 2.2 bars.
                Just a tip here....

                I had a similar problem..... it was scale in the pipe to the gauge and in the little "pin hole" in the coupling at the back of the gauge....

                Descaled the pipe and cleaned out the pin hole with of all things - a pin :(very carefully as there is a diaphragm at the end of the hole which can be easily damaged)..... cleaned away the powdered scale which I had dislodged..... reassembled.... and hey presto.... 5.1 Bar at rest (supply pressure) which rapidy increases to 9 Bar when the pump kicks in - all is good. ;D ;D

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                • #23
                  Re: Upgraditis: 2-group Grimac Commercial

                  Thanks JavaB, when things cool down tomorrow the gauge will be looked at.

                  My descaling wasnt the best, as you say.

                  What I did was remove two pipes to the bottom of the boiler, and two at the top..

                  First I flushed water through to dislode any loose material -- dont know how long this machine has been in storage.

                  Then I put back the bottom pipes, and filled the tank with hot water and citric acid -- but did not run the mix throughthe system.

                  I let it sit, and then removed the bottom pipes again  so the mixture with all its yellow crud could go through those holes only.

                  Similar routine for the heat exchangers.  

                  But now that I know the machine works, Ill descale again in-situ.

                  At the moment it is not plumbed in --- its getting filtered water from a huge steel  kitchen pot.  So itll be easy to put citric acid into that.

                  --Robusto

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                  • #24
                    Re: Upgraditis: 2-group Grimac Commercial

                    Another update.

                    I spent 15 hours on the machine, and was so tired sleep was difficult.

                    The inoperative pressure gauge. Unfortunately the problem is deeper than clearing the pump inlet with a pin.

                    On dismantling it, it works similar to a dial thermometer with an expanding bimetal coil which in turn moves clockwork-like cogs.

                    A tiny little arm connecting the coil to the rest of the works is broken. Im going to attempt to solder it, but dont like my chances. Even if I succeed, the calibration will probably be out.

                    Could be that a new guage is in order.

                    --Robusto

                    Comment


                    • #25
                      Re: Upgraditis: 2-group Grimac Commercial

                      Robusto

                      Now thats dedication!

                      It takes quite a bit of time to undo the years of little (or poor) maintenance which most of these machines have had. Its a tribute to their makers that they have "soldiered on" for so long and still made great coffee.

                      Its a pity about the gauge - I was more fortunate - but careful soldering should work. Not a lot of stress on that bit (unlike the person doing the restoration ).

                      Many see these machines as a sledge hammer to crack a walnut.... but the taste of the walnut is just soooooooo good..... and the satisfaction that comes with knowing you restored it yourself - priceless!! ;D

                      Not too much longer now.

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                      • #26
                        Re: Upgraditis: 2-group Grimac Commercial

                        I am impressed... pulling a pressure gauge apart is pretty serious business.

                        New gauges should run about $70-$100 depending on who you get it from.

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                        • #27
                          Re: Upgraditis: 2-group Grimac Commercial

                          Pulling the gauge apart was a very simple operation -- two grub screws hold the cylindrical case to the internals.

                          I think the skills of a clock maker would better serve the repair, however.

                          Holding something the size of a 10 mm pin with 2 mm eyelets at each end and trying to position it is no easy task.

                          In any case, after hours of fiddling around, I made a new part from a paper clip, hammering the ends to flatten them, and forming eyelets out of them. (it looks like a dumbell, but all flat)

                          However, that hasnt solved the problem. The springy bimetal tube which expands according to pressure, pulls back too much so that the gauge pointer does not reset to zero.

                          The RPM brand rotary pump is self-priming, and for now Ive now droped the intale hose into a 10-litre bottled water container which Ive filled with Brita filtered water.

                          The pressurestat cycling on and off is quite a loud click. Probably accentuated by the covers being off the machine.


                          But the main thing is that everything (except the pressure gauge) works, and there are no leaks.

                          The group seals will have to wait. Too tired today. They do seal and Im warming her up for an espresso.

                          --Robusto

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                          • #28
                            Re: Upgraditis: 2-group Grimac Commercial

                            Originally posted by robusto link=1173088713/15#26 date=1173230327
                            However,  that hasnt solved the problem.  The springy   bimetal tube which expands according to pressure, pulls back too much so that the gauge pointer does not reset to zero.
                            Is it possible to rotate the face?

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                            • #29
                              Re: Upgraditis: 2-group Grimac Commercial

                              Originally posted by Thundergod link=1173088713/15#27 date=1173231290
                              Originally posted by robusto link=1173088713/15#26 date=1173230327
                              However, that hasnt solved the problem. The springy bimetal tube which expands according to pressure, pulls back too much so that the gauge pointer does not reset to zero.
                              Is it possible to rotate the face?
                              Generally the needle on most gauges is a press fit to the shaft and can be (carefully) rotated to set the zero.

                              Also make sure you dont suffer from the same problem Mark has where - because there is no pressure on the water in the heat exchanger (normally at mains supply pressure)- the water in it will boil (being heated to 125C or thereabouts......) Mark has had this boiling water / steam flow back via the pump and into his reservoir... (not good for the pump either I would imagine )

                              Will also make for some interesting cooling flushes as the heat exchanger (normally full of water) will be dry!! :-/ :-/

                              Comment


                              • #30
                                Re: Upgraditis: 2-group Grimac Commercial

                                Gulp. Thats an ugly thought. The Grinders technician said it was OK to run water from a tank. But on the other hand, I know some machines do want a head of mains pressure.

                                I dont want my cooling flush to be the steaming part of coffee making!

                                -Robusto

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