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Frequent cycling of fresh water inlet...

FWIW my water inlet pressure is 48psi (3.3BAR) via regulator. And I'm running a 120v pump, accumulator and bottle system to feed my LI.

The cycling of inlet water to the boiler is disruptive to pulling 2-3-shots in a row (with about 5-10 minutes between shots). I need, to prevent cold water from entering the boiler, to flush a fair (sorry no measurement for this) amount of water between shots to cycle the inlet of cold water to the boiler so that cold water isn’t triggered to flow into the boiler during pre-infusion phase (and subsequently lowering of the boiler pressure…and thus pre-infusion pressure).

So, does it sound normal? Is this just a manifestation of a relatively small volume boiler?

Thanks,

Dan

Comments

  • From my days with the line fed L1 I don't recall anything like what you describe but I must say it is not exactly clear to me either what precisely you mean. Can you write, film, or otherwise illustrate/document it more clearly?
  • I'll make a video tomorrow morning. More often than not, when pulling the lever down for PI the boiler "asks" for more water unless I purge enough water from the group to initiate cold water feed into the boiler. And that effects group temp for brew water.

    Cold water feed into the boiler lowers the boiler pressure which alters the PI pressure (and to a lesser degree brew water temp) which alters what I get in the cup.
  • Why purge water through the group? That would send the temperature of it all over the place. If you use the hot water tap that would have the same effect for you won't it?

    I used the steam wand to initiate the heating element and in effect a high boiler pressure just before pulling. If some water is then drawn into the boiler, this does not have any effect on the hot water that has already flown through the group onto the puck and by that time I would have raised the lever to extract the coffee and any boiler pressure is unimportant. That's how I remember it.

    Maybe I should look up old videos where I must have documented the routine in detail.
  • hi dan

    I've read and re-read this thread and I'm afraid i can't quite picture the scenario

    unless you've changed the machine in some way, you will pull the lever down, pre-infuse, release lever, wait for shot to complete, remove portafilter, pull the lever partially down momentarily to release 50-60mL, job done

    the machine will be at the correct temperature for the next shot as fast as you can prepare the basket

    a long flush of the group prior to the shot will screw everything up, everytime

    kind regards

    reiss.
  • Reiss Gunson post=11483 wrote:

    unless you've changed the machine in some way, you will pull the lever down, pre-infuse, release lever, wait for shot to complete, remove portafilter, pull the lever partially down momentarily to release 50-60mL, job done

    reiss.

    New Year, so I was looking at my current routine, and I do it exactly as you described. However, I have a question about after the shot purge.
    What is the purpose of this task? Is it only to clean the shower screen or it is also needed to "reset" thermosiphon (something about this was mentioned in early days of Londinium, not sure if still needed with LR)?
    Basically, if I do few shots in a row, should I do the purge after every shot, or is it enough to just use espazzola at the end of the espresso session?
  • hi pawel

    on the L1(2012-16) the brief post shot flush cleans the screen (ideally performed with the Espazzola) and clears any water vapour from the thermosiphon if flash boiling has occurred

    on the LR/1/2/3 the brief post shot flush (ideally performed with the Espazzola) is only performed to clean the screen as the lower boiler pressure of 1.0 bar ensures flash boiling does not occur

    it is more than adequate to rinse the screen after a session on the LR/1/2/3, even end of day is enough. if you have allowed coffee tars to form on the screen spraying the Espazzola with citrus solvent before affixing it to the group works like magic

    kind regards

    reiss.
  • Thanks Reiss,

    All clear.

    If you don't mind, one more question.

    Using the hot water from boiler. I found as always different opinions, so wanted to ask you directly.
    I steam milk let say 10-15 times per week.
    Is it recommended to use the water tap to release some water from the boiler ( from time to time, to heat the glass, etc).? What I read is that if you use only steam, then some scale may build easier inside the boiler, as only steam escapes the boiler, we add new water, so even if the water is soft, the amount of minerals is increasing over time.
    The second opinion from some technicians I heard was, that the worst boiler confirmation they have seen is from machines that were serving almost like kettles (water for americaons, tea, etc.).
    What would be your recommendation, taking into consideration only long life of the machine.
  • my recommendation is you get your water chemistry correct and then you can use the machine as you please

    i use no filtration whatsoever on my machine (because the water is soft enough) and we use it as a hot water kettle instead of boiling the jug all the time and it works just fine

    my expectation would be that if you were using hard water in the machine then every time you run water off the boiler and the boiler is refilled than that new water will have a higher level of scaling compounds and that will precipitate out, increasing the scaling

    conversely, the usual objection to HX machines is that if you are not drawing water off the boiler now and then it goes stale and tastes unpleasant if you make a hot drink with it after some weeks or months of it lying in the boiler

    so in my view you will draw water off the boiler at least once a week to keep the water fresh in the boiler and you will get your water chemistry right so the TDS is high yet the scaling compounds (calcium carbonate, magnesium carbonate) that are a subset of that TDS value are low and never greater than 70ppm and ideally less than 50ppm

    kind regards

    reiss.
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