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LR Digital PI Module Installed and Pump Issues

Hi,

I've had my LR since late summer/early fall and recently installed the digital preinfusion module upgrade a little over a week ago. However, I've recently started experiencing some issues with the pump. The last couple of times I've turned on the machine manually to adjust the PI setting the pump has come on and run continuously for many seconds (and it was not filling the tank). It eventually turned off by itself but, again, running much longer than normal. The pump has also started to turn itself on briefly at random moments (pulsing briefly) without the lever being pulled . Another thing that's just started to happen is when pulling the lever for a brief flush the pump will not come on as has been the usual behavior before the PI module was installed. Interestingly, these problems seemed to start occurring (or become more noticeable) when I went from a pressure setting of around 2.1 - 2.3 bar (which I had been using up until yesterday) to 4 bar and over (was experimenting with 5 and then 6 bar PI settings earlier in the day). One other data point, is several weeks before the module was installed my son reported that he'd had to turn the machine off when he heard the pump running continuously. I was skeptical this had occurred as I had never heard the pump run for longish periods like that -- until yesterday.

I had a few lingering questions of whether the machine was coming up to temperature. I sometimes informally gauge the temperature readiness to pull a shot after at least 45 minutes of warm-up by putting my hand on the bare metal of the lever handle and feeling how long I can comfortably hold it there. Usually only very briefly. However, it seems after the upgrade as if I can grab the bare handle longer than usual, although, admittedly, I can't really be sure of this it just feels like it.

I did slide/pivot the machine sideways on my counter to better get at the module to change the PI settings (since found I didn't need to do that to make adjustments, fortunately). I came across a post (will have to find it again) where you referred to a connection possibly being loosened by the vibration of sliding rather than lifting the machine. Also, while the PI module install seemed to go well enough, it was difficult to fit my spanner on the transducer pipe end connector due to the angle of the manifold and the width of the spanner but I tightened it the best that I could (also applied Loxeal). Also, I did not remove the water reservoir when doing the PI module upgrade.

Thanks for your help.

Carl

Comments

  • hi carl

    its probably easier for you and me if you video call me on FaceTime ([email protected]) or WhatsApp (+642040564412)

    i suspect your pump running for a long time and not getting anywhere at higher pre-infusion pressure settings will be due to the pressure adjustment screw mounted on the very bottom of the pump being too far open

    this adjustment screw hangs out through the bottom of the chassis and it easiest to adjust with a 10mm ring spanner

    the quickest way to adjust it is probably to screw it all the way in then wind it out two complete turns; that should ensure the pump can deliver at a pressure greater than the highest pre-infusion setting, which is 6 + 1 (offset) = 7 bar

    if i were you i would make that change first and see what effect it has

    i look forward to hearing from you in the near future

    kind regards

    reiss.
  • Hi Reiss,

    I'll give this adjustment a try (later this evening) and report back.

    Thanks!

    Carl
  • Reiss,

    I was able to turn the screw beyond flush with the bottom of the chassis. It still wanted to turn further but because of the awkward angle to get at the bottom of the machine I stopped there, then backed off two turns. So now the screw protrudes somewhat less than it did originally.

    At power on the pump no longer turns on by itself and run continuously for 30 seconds or however long (a good sign).

    I started out set to 4 bar and, as before, noticed no pulsing and now a much shorter (but still noticeable) delay when pulling the lever for a brief flush (as for cleaning shower screen). Not almost instantaneous when pulling the lever as before the update but noticeably more responsive than before the screw adjustment. Also, subjective evidence, perhaps, but the metal handle also seems hotter (than it had felt after the mod) and more like I had normally come to expect after warmup. IOW, I can't grab it for more than a moment or so before needing to take my hand away.

    Pulled a shot at 4 bar and all seemed normal. So far so good. Next, set the machine to 6 bar. Left the kitchen for a few minutes and came back to hear the sound of the pump pulsing intermittently on its own, but shorter, fainter, pulses this time. More like the occasional stutter. I then set it to 5 bar whereupon the intermittent pulsing went away (or at least for the time that I listened). Finally, I set the pressure back to 4 bar (making my way through a bag of light roasted beans) and left it there.

    It seems like the pump adjustment screw is the ticket but maybe needs a slight tweak. Would you say a half turn -- clockwise -- since I did not turn the screw completely to the end of travel against the chassis.

    The short delay of the pump coming on when doing a brief flush for cleaning shower screen seems to waste a bit more water. Maybe that 1/2 turn or so (if recommended) will also l bring it back to 'normal' or perhaps this slight delay when pulling the lever what I might expect?

    My settings are: PUMP 500ms, Offset -1.0, Bar 4.0


    Carl
    Reiss Gunson post=15589 wrote: hi carl

    its probably easier for you and me if you video call me on FaceTime ([email protected]) or WhatsApp (+642040564412)

    i suspect your pump running for a long time and not getting anywhere at higher pre-infusion pressure settings will be due to the pressure adjustment screw mounted on the very bottom of the pump being too far open

    this adjustment screw hangs out through the bottom of the chassis and it easiest to adjust with a 10mm ring spanner

    the quickest way to adjust it is probably to screw it all the way in then wind it out two complete turns; that should ensure the pump can deliver at a pressure greater than the highest pre-infusion setting, which is 6 + 1 (offset) = 7 bar

    if i were you i would make that change first and see what effect it has

    i look forward to hearing from you in the near future

    kind regards

    reiss.
  • hi carl

    the hesitation before the pump turns on reflects the 500mS pump delay you have - reduce this value to 100mS if you want the pump to turn on faster

    which metal handle are you referring to? if you mean the lever arm the correct place to hold it is on the solid wenge handle

    if you haven't got an offset ring spanner then use an open faced set spanner to make to full adjustment to the pump pressure screw

    let me know how you get on

    kind regards

    reiss.
  • Will try adjusting the pump setting to 100 ms (or 200ms).

    Ah, sorry for the confusion -- I certainly pull shots by the Wenge handle -- but I sometimes make a rough check that the machine is up to temp after 45 minutes or so by placing my hand on the metal portion of the lever.

    I'll try to get back at that screw but will have to enlist my 'helper', again. :) I do have small socket wrench.

    Thanks.

    Carl
  • Hi Reiss,

    I adjusted the pump down to 100ms and it works much better, 200 ms was also ok (slightly more delay but either would be fine).

    I used my ratchet handle with 10mm socket to turn the screw clockwise to the end of the thread. It seemed to take several more turns then when I stopped on my previous attempt (went deeper into the chassis) and then I backed out two turns. Now, the pump is (again) silent up to 5 bar but at 6 bar there's still some -- although much less -- stuttering as before. Seems like it could perhaps use another half turn or so clockwise (into the pump body), maybe? I don't know how often I would go above 5 bar but I can tweak it a bit if that's ok?

    Again, this adjustment screw seems to be where the issue lies.

    Thanks.

    Carl
  • hi carl

    try turning the pressure adjustment screw in another 1/2 turn perhaps

    kind regards

    reiss.
  • Hi Reiss,

    Latest updates, more data points, some contradictory results.

    I had the machine on much of this past weekend and then the usual 2-3 hours on Monday without a peep from the pump at 4 bar. However, on Tuesday morning there was once again some spontaneous pump noise (odd since for several days it had been silent) so I made the adjustment on Tuesday evening (last night). Turning the rotary pump adjustment screw a further 1/2 turn clockwise into the body as suggested. However, the result was there was actually _more_ intermittent pulsing of the pump rather than less once the machine had warmed up (it's on a timer).

    I would describe it as a series of short pulses (that would repeat 3x) and would start during the low part of the pressure stat cycle, just before I could hear the sound of the heater turning back on. Short flushes didn't have any effect but I found after pulling a shot the pulsing went away. Ok, back to normal, kind of.

    I then pulled off the side panel and set the preinfusion pressure up to 6 bar whereupon the pulsing started again in short order (as I had experienced earlier at 6 bar). I turned it back down to 4 bar, pulled another shot, steamed, and then shut the machine off.

    Tonight I was planning to back off the half turn (counter-clockwise back to approx. where I started) or perhaps a bit more. I don't know how much of a difference that will make but hopefully it will quiet it down at 4 bar. Would seem like the pattern of it happening just before the heating cycle begins is a clue? I don't know how often I would go above 4 bar, which seems to have worked well for the light roasts I've been using since the upgrade. I'm just about finished with a bag (a Rwandan SO) and will be trying a darker roast shortly where I plan to start out with a preinfusion setting of around 2 bar or so.

    The adjustment screw is now about flush with the chassis plate, whereas previously (before the preinfusion module upgrade) it was protruding out somewhat and I could actually get my small spanner onto it. Now I use a 10mm socket and gently turn.

    These rotary pump issues aside I'm impressed with the flexibility offered by the preinfusion module. The pump sound is annoying but at 4 bar it's a question of whether it presents an issue or not (6 bar def. being problematic). At 4 bar when when it did pulse on its own it seemed to go away after I pulled a shot. I'm sure this isn't quite the expected behavior so I'll look forward to hearing any further suggestions.

    Thanks.

    Carl
  • hi carl

    easy enough to resolve

    have the right side panel that covers the console of the pressure transducer removed so you can see it

    can you please pull the lever only just down to let out a tiny amount of water - 15mL would be enough

    immediately start observing the upper of the two numbers shown on the pressure transducer console

    what is the highest number it displays before it starts to fall back again?

    (this pressure reading taken at the transducer cycles up and down in response to the cycling of the heating element in the boiler)

    kind regards

    reiss.
  • OK, will do.

    Heated up for about 35 minutes or so before doing a short pull of the lever. Had to do it a few times to get to 13ml, as it was usually more or less water but that didn't seem to change the max readout much. It seemed to pretty consistently go up to 7.4 before starting to decline again.

    Without pulling the lever, at the end of the heating cycle (when the pstat clicks off) the display reaches 7.8 max. At this point in the warmup phase (less than 45 min since turn on) the display would bottom out at around 5.0/5.2.

    Then, at around 45 minutes or so the pump started to do its stutter thing. I noticed this would happen when the display would show 4.1. Hmmmmm....?

    Also note, I left the pump adjustment screw unchanged (1 1/2 turns from closed).

    Carl
  • hi carl

    i have put the instructions you need in the permanent file so others can find it easily in future; https://londiniumespresso.com/permanent-file/1336-does-the-pump-stutter-on-and-off-repeatedly-when-the-lr-is-idle#15670

    kind regards


    reiss.
  • ps - im not saying you need to run out an exact volume of water, im just saying you only need to release a small volume of water from the group in order for the pump to replenish the pre-infusion circuit with cold water, which will in turn ensure the static pressure in the circuit is driven up to the point at which the expansion valve will open.
  • Hi Reiss,

    Thanks for the clear instructions. I'll make the adjustment this evening. :)

    Carl
  • ignore my advice to raise the pressure in the pre-infusion circuit quickly by pulling the lever and introducing cold water (which quickly produces thermal expansion in a hot system)

    instead briefly open the steam wand to force the heating element on so the pressure in the pre-infusion circuit is pushed back up to the top of the cycle again

    when the pre-infusion 'Set' value is 6 bar the pressure in the pre-infusion circuit will range from a bit above 6 bar up to about 11 bar

    all you are doing is tightening the expansion valve a little so you slide this whole range of pressure movement upwards, both the maximum and minimum values

    in this way as long as the minimum value stays nicely above 6 bar the pump will not start turning on and off rapidly as it attempts to lift the pressure above the 'Set' value of 6 bar whilst the pressure in the pre-infusion circuit continues to fall until the heating element from the boiler turns on to commence the next heating cycle

    best

    reiss.
  • Ok. Got it. Steam wand. Good explanation of what's going on.

    Thanks!

    Carl
  • Adjustment done. Hardest part was getting the silicone drain tube off the brass nipple. The pump quieted down and the display moves between 6.0 and 11.4 +/-

    Hopefully problem solved.

    For now I've turned the preinfusion down to 2.1 bar for some medium-roast beans but next I'll likely look for a lighter roast that will allow me try 4 bar or better.

    Thanks, again!

    Carl
  • good. thanks for reporting back carl.
  • Ha! Thought I was done but maybe a bit more fine tuning. . Ok, one more thing. Dialing in a different coffee and after pulling a couple of shots wanting to tweak the preinfusion setting -- I have the side panel off again -- now seeing up to 12.2 as the upper range on the display and a 'Check Expansion Valve' message. Presumably I should back off some fraction of a turn from yesterday?
  • Hi Carl

    We coded in that message to appear if the displayed pressure exceeds 12.7 bar - it is purely a note, it does not mean any kind of failure has occurred - just a flag to say it’s set a bit high

    Turn the adjustment screw anti clockwise one eighth of a turn at a guess and then observe for a few cycles of the boiler element

    Kind regards

    Reiss
  • Yes, I turned it back down about a quarter of a turn -- the effect of turning the screw is not quite linear as you noted previously. I used the steam wand a few times, pulled a couple of shots and observed it would occasionally go to 12.1 - 12.2 bar but usually in the 11's.

    Moral of the story, perhaps, is pull some shots as well as send some water through the steam wand and observe the results on the display. Good to know about the message.

    Seems good.

    Thanks, again.

    Carl
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