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Thermosyphon dry, no initial shot pressure ECM Technika

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  • Mono
    commented on 's reply
    Yeah, that would make sense as my previous machine steamed the top cups up but this one doesn’t. Previous machine was a HX Rocket that vented the anti vac to the inside of the cabinet and from memory it used to drip for awhile during heat, maybe not to the same extent…

  • steve7
    commented on 's reply
    I was looking at the exploded parts diagram and I thought I saw the Sync had a tee-junction off the anti-vac for a drain. Mine does not and just fogs up the cups warming on top until it closes.

  • Mono
    replied
    hmm, I have the ECM Sync. I'll pull the top off a have a peek. mine definitely drips away for some time as it heats

    Leave a comment:


  • steve7
    replied
    Originally posted by Mono View Post

    ….as in NOT the group head exhaust,…..
    That is correct. It is not the group head exhaust. The outlet is on the front panel, behind the group head exhaust, as in the photo. It can’t be seen, but there is a hole in the bottom of that cylinder for the water to drain into the tray.

    Looking at the internals, this outlet has a clear plastic tube going to a 4-way connection that has the pump output coming in along with the top and bottom pipes of the HX, which is why I believe it might be the OPV.

    As best I can work out, the anti-vac valve on top of the boiler has no pipe running to an outlet - it just vents out through the holes in the top of the machine until the pressure closes it. Unless the HX has it’s own anti-vac valve?

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  • Mono
    replied
    Originally posted by steve7 View Post

    Do other people have water dripping from their OPV exhaust in the heat-up phase?
    Now I’m guessing you mean it as you have written as in NOT the group head exhaust, reading it that way it’s a yes as I believe that is also the anti vac valve drain on ECM machines. Front of the front fascia panel….

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  • steve7
    replied
    The big flush with the dismantled mushroom seems to have blown something out, so the thermosyphon is now working.

    But I have kept an eye on the exhaust mentioned by @EspressoAdventure. When the machine is heating up, water is dripping into the tray. Once at or close to operating temp, there are no more drips. I don’t know whether that means I have a leak.

    Do other people have water dripping from their OPV exhaust in the heat-up phase?

    Leave a comment:


  • steve7
    replied
    Thanks for the suggestion. I assume that is an overpressure valve outlet? I think it is on the front panel just behind the group head exhaust:

    Click image for larger version  Name:	AD0D2A7F-C65F-4274-8051-8B9144FC479E.jpeg Views:	0 Size:	305.2 ** ID:	889804
    I have kept on eye on that and didn’t notice many drips coming out. I would assume the pressure would build up a fair bit during the heating and certainly during a shot. (Ignore the round piece in top-left - that’s for my mirror to see the shot out of the naked basket)

    I took the mushroom off and gave it a good flush in case something had lodged - looked to be good flow from both holes. I also used a straw to blow air through the top hole - there wasn’t much resistance so I assume all okay. I took all the panels off to see if there were any steam leaks when under heat - nothing. I also took a hose off the pump and blew some air through and there didn’t seem much resistance, so I assume no blockage.

    After the big flush and checking the mushroom thoroughly, it appears to be working better - but I’ll have to give it a longer run. The other possibility was a stall in the thermosyphon.
    Attached Files

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  • EspressoAdventurer
    replied
    Steve IIRC these have a concealed exhaust. Behind the front panel vs others brands running an exposed exhaust.
    Id suggest you check that the brew chamber is not leaking down whilst idling which wouldn't be immediately evident given the above.

    Leave a comment:


  • steve7
    replied
    Just as a further thought - I cannot be sure the thermosyphon is dry - that is just a wild guess. It might be the mixing valve (expansion valve?) from the pump into the thermosyphon circuit could be at fault - and maybe it is getting stuck as it heats up from the thermosyphon action.

    Leave a comment:


  • steve7
    started a topic Thermosyphon dry, no initial shot pressure ECM Technika

    Thermosyphon dry, no initial shot pressure ECM Technika

    I've just had this develop on my Technika IV (rotary pump - water tank). I think the heading sums it up and I am looking for inspiration.

    When first turned on (ie cold) if I lift the lever I immediately get water coming out of the screen and the pressure gauge goes to 8/9 bar, which is usual.

    The machine starts to heat (boiler pressure ok) but when the group head gets to just over 80 degrees according to the group head thermometer it stops heating. The group head thermometer would normally get to 96-98 degrees and stabilise depending on ambient temps.

    If I then lift the lever, the pump comes on but there is no water coming from the screen and no pressure on the gauge for a few seconds. After the few seconds water does come out and the gauge reading is what I would expect. Repeating that 10 seconds later, I still get a delay, even though I assume the system is primed.

    I left the lever at the halfway mark and it seemed to be heating, but as soon as I activated it, the temp dropped.

    If I put a blind filter basket on, after the delay it will go to about 10-bar which is what has been normal.... so the pressure from the pump seems okay.

    It appears the thermosyphon might have drained and so the pump appears to not be primed... and there is no water circulating to heat the group head once it gets to a certain point.

    I assumed maybe the seals in the group head were leaking (there were a couple of drips) and so the system was depressurising. I have changed the seals, but still nothing. The fact that it holds pressure with the blind basket makes me think it is tight. And - there are no water puddles under the machine.

    I recently descaled the machine and did get some odd pressure readings for a while (gone now), so dislodged calcium passed my mind, but I would expect a blockage to be a blockage - hot or cold.

    Any thoughts?
    • Is there a drain valve that might be heat effected?
    • Would the pump be affected by heat - even though it has normal pressure once primed?
    I am stumped.
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