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Gicar 1d5e volumetric controller / board issue

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  • Gicar 1d5e volumetric controller / board issue

    Hello all,

    I've been working to bring back to life a fairly well worn Boema 2 Group volumetric - probably about 10 years old, what what I can find. After a through descale and deep clean, and replacement 2200 watt element, it's running nicely (and can run on 10amp GPO)

    However, since it got up and running, I've found a new issue. One of the Gicar volumetric controllers (1d5e - 8.5.68.32/A) is switching itself 'off' when the machine gets up to temp.
    When cold, it switches on (lights blink on power) and works normally. But once the machine gets hot, it just won't respond.

    I've replaced the capacitor on the board - as I had an appropriate one on hand, and this hasn't helped - the same thing keeps happening. I'm wondering what the next step should be.

    Does anybody know which components are most likely to fail due to heat? I think the next step is to replace transformer and relays - but I'm having trouble finding the specs for these.

    I'm also not entirely convinced by my 'heat failure' hypothesis, so thought I'd put this one out there - because I can't think of any other explanation. Could it be something else?

    Any advice or help much appreciated!
    ash

  • #2
    The transformers generally fail in controllers due to the heat and stress, in that particular type of integrated touchpad/controller (fairly sure that's what yours is) it happens fairly regularly.
    The other part that can fail is the main element relay.

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    • #3
      Cheers! Yes - it's an integrated touch pad/controller, and mounted above the group.

      Looks like some more fun with the soldering iron...

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      • #4
        Parts are cheap fortunately, the transformers can be sourced for under $10 from RS Components. Relays much the same.

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        • #5
          It's funny you should mention that - I've been trying to find replacement components at RS. Nothing quite seems to match-up with what's on the board, and I don't have the expertise to know what values are flexible...

          The transformer is a HAHN BV EI 304 2082 230V 50-60Hz 12V 2,1VA
          Click image for larger version

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          and I think the closest I can find is either under the 2.1VA: at 2.0VA ( https://au.rs-online.com/web/p/pcb-t...rmers/7320360/ )
          OR over at 2.8VA ( https://au.rs-online.com/web/p/products/7320389/ )

          RL3 is a JQX-14FW 018-HS - which the data sheet I can find says has an 18V coil, SPST-NO configuration and is sealed.
          Click image for larger version

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          This one I'm really struggling to find an equivalent.

          The other two, RL1 and RL2 are OMRON G2RL-2A 18VDC, which I'm also having trouble finding.
          Click image for larger version

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          Any advice about what might be substituted would be much appreciated. I've been doing a lot of reading, but it's a steep learning curve!

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          • #6
            I'd use the 2.8 VA Tx if it will fit (check clearance to the cover on the Gicar unit), overrating the Tx ensures it will run a bit cooler and hopefully last a bit longer.

            For RL3 you could use RS part 718-1991 18V 16A SPDT relay, just cut off the NC pins and you have an NO relay.

            Assuming this is the element relay, an alternative would be to pick the relay drive voltage off the board and take it to an SSR mounted on the chassis.

            I can't help with a direct replacement for the 18V Omron relay. It is possible to convert to 12V but it's a bit of dicking around.
            Last edited by Lyrebird; 28 August 2019, 11:26 PM.

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            • #7
              Thanks Lyrebird - that's really helpful.
              I'll replace these two parts first, and see what happens!
              Also - hadn't even thought to check clearance - good point! After a quick measure, it's pretty tight, it looks like I'll got for the 2.0VA.

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              • #8
                If you substitute a lower rated Tx is will run hotter and fail earlier. I would advise against that unless you also do the SSR mod: the SSR takes much less drive current than a mechanical relay so it reduces the total load on the board. It will also last longer.

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                • #9
                  That's a real catch 22! I'll either have to modify the controller unit box somehow to fit in a bigger transformer, or run out to an SSR...

                  However, now I'm wondering exactly what that 16 amp relay is responsible for switching.

                  There machine runs just fine with the volumetric pad/controller out of action - the manual switches continue to work, and boiler cycles as normal. So I'm assuming that this controller is switching on the rotary pump and some solenoids.

                  There's also another box under the drip tray that seems to be handling the boiler auto-fill. Looks like my next task is to try and make sense of the tangled bunches of wire.

                  Thanks again, by the way. I really do appreciate the advice. I've been away from this forum for a while, and had forgotten how great this community is.

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                  • #10
                    OK that's interesting, I'd assumed it's the heating element but it might be the pump motor: motors are a bastard of a load to switch (very inductive) so it's usual to over rate a relay significantly.

                    BTW the above applies to SSRs as well: good info from Crydom re SSRs and motors here.

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                    • #11
                      Cheers! I've got my hands on a BOEMA parts list, which shows (sort of) their configuration. I'll put the pic below as it might be helpful to others (and I'll try to upload the whole pdf on the documentation page).
                      Click image for larger version

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                      It looks like there is an RL40 main control board, and a volumetric unit (in my case, two). I think you're right - that relay is probably switching the pump.

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                      • #12
                        Parts arrived - and problem solved!

                        Took the time to put in the new components one at a time - to try and isolate the issue, and nailed it first try: the transformer (just as noidle22 suggested).

                        Machine working a treat now, and I've been pulling coffee all weekend. Despite not being designed with much consideration of ergonomics, I'm impressed with the shots coming out the machine. It's pretty forgiving.

                        After noting a fairly high pump pressure when just purging the groups, I'd be interested to know what from other Boema owners what kind of pump pressure they read when running water through the groups (ie - with no coffee).

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                        • #13
                          I would say pressure through the groups without portafilters should be the same 9 bar as with a blind basket or loaded portafilter.

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                          • #14
                            With little resistance to water flow, the observed pressure should be significantly less that normal brew water pressure. Hard to say what this will be exactly given that there may be gicleurs fitted into this hydraulic circuit...

                            Mal.

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                            • #15
                              Hi Robusto and Mal, yes, I'm getting roughly the same 9 bar reading with and without loaded portafilter. A tiny smidge higher with a blind basket.
                              I had thought that the resistance would be much lower, like you suggest Mal, and was trying to think if there could be a blockage somewhere, but was getting the same reading on both groups, and a much lower pressure when filling the tank (around 3 bar). Then I found the pretty small restrictor/gicleur that's a part of each group, and figured they could be providing the resistance. I am surprised that it is so high.
                              It's also worth noting the brew pressure gauge is looking a bit tired (was stuck initially, and showing nothing) so I don't have the greatest faith in its accuracy. Next on the list of parts to replace, I think.

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