Hi, all. My Lelit Elizabeth v3 is around 3 months old now, and has started to behave a little strangely with regard to pressure. If I put in the blind basket, then engage the pump (no preinfusion, and it's been an hour or so since last use), the pressure spikes up to around 11 bar, then drops quickly to around 10 and holds. If I then do this again very soon after the first time, the pressure will only go to maybe 9.5 bars and hold. Then on the third such run, and all subsequent runs in this sequence, it will just go to 9 and hold there. Something very similar happens with coffee in the portafilter, though the pressures there decline during the shot as expected. I have found on other message boards that a few others have also had this problem, but I haven't really found any solution. One person suggested adjusting the OPV, which I had already done long before this issue arose to set it to 9 from the factory default of 10. I did adjust it again just to see, and it did not seem to help. In fact, when I adjusted it I set it to around 8.5 bars (as the pressure it gives after several runs in a row with the blind basket at least), but the next day it was back to its previous level and behavior, as if the OPV adjustment had undone itself. Is this a case of a bad OPV? How difficult is it to change out the OPV entirely?

> @"Pygmalion"#p1227 Is this a case of a bad OPV? How difficult is it to change out the OPV entirely? it's not difficult, but it's very unlikely that the expansion valve (OPV) has gone bad. If it had you would probably be getting other sumptoms. For the OPV to cause the behaviour you're describing, it would have to be stiffer and open later for the first shot, then open a bit further when the pressure drops to 10 bar. Then as you do more shots…it is loosening up. That' not really normal behaviour for that type of valve. If it was sticky, then usually it would jam up on other shots, possibly randomly…it's also very hard for it to stick. As you can see, the only bit that moves is the pad, held by the spring against the port. There is not much to stick or jam. The only par that could is the relatively loose fitting metal bit with a pad. [URL=https://i.imgur.com/fX9CLwu.png][IMG]https://i.imgur.com/fX9CLwu.png[/IMG] From your description, the behaviour seems to follow a consistent pattern, which would indicate another cause. I'm just not sure what at the moment?

@"DavecUK"#p1229 Thanks for the detailed reply DavecUK (BTW, I'm using your advanced parameters for the Elizabeth; thanks!). I wonder what could cause an issue like this, then? Could it be a temperature thing? That is, the first shot might be hotter (if I haven't done a purge, which I often don't), then subsequent ones in somewhat rapid succession are a little cooler, etc. Would this make the pressure behave in this way? My understanding of the OPV is that it sets an upper limit on the pressure, and that it should never rise above this if the OPV is working correctly. Of course, that's only the pressure at the OPV itself, which is not directly what the pressure gauge is reading (pump pressure?). So, if the OPV is not the problem, then it could be the gauge I guess, or it could be that somehow the pressure in the system where the gauge is reading is higher than the OPV in some strange, consistent-ish way. Anyone else having similar behavior?

@"Pygmalion"#p1238 In a rotary pumped machine, odd things can happen because the water goes into a sealed system through a 1 way valve. The expansion valve in that sealed system is set to 12 to 14 bar. In your system it's the expansion valve as you correctly say controlling the pressure, so there is an upper limit….not really sure…am cogitatingt. I even though perhaps air in the capillary tube, but that wouldn't case the problem you're getting.

Morning all, I noticed this morning that I have the exact same thing happen! Preheated for about 40 mins, purged for 3-5 seconds out of the hot water tap, waited a minute or 2, puled a shot with a 10 second preinfusion at 2 bar, after the 10 seconds it shot up to 10-10.5 bar before dropping back to 8.5. Subsequent shots only reached 8.5 bar after PI (I did another 2, one for my wife, the other for 'science', aka my second double before 0700 what could go wrong). The strange thing is, the timings were all exaclty the same, 16g in, 33 out in 33 seconds. I'm wondering if it's more of an issue with the display then with the valve? I've possibly got some friends coming over tomorrow for a pre/post run brew so if I do more then 3 shots I'll pay close attention to the needle and report back...

I've thought about what might be happening by imagineering how I this could be created if one wanted to do so. and looking at the way the Elizabeths were made (factory photos of first production run…I can't see how it can happen, or be made to happen, unless i'm missing something. The repositioning of the expansion valve is still within the sealed brew area, and they changed it for a much better and reachable/adjustable valve. The V2 I had which I modified to a V3 still; has the old valve, as you can see from my review photos, and hydraulically is in essentially the same position (if not physically) https://coffeeequipmentreviews.wordpress.com/2020/05/08/lelit-elizabeth/ So here is the image, just to orient people 1. Expansion valve controlling brew pressure max 2. Manometer take-off for pressure gauge 3. Autofill solenoid for steam boiler, opens to fill steam boiler 4. Exit port from ring group to vent solenoid 5. Vent solenoid, opens at end of shot. As you can see 1, 2 and 4 , all form part of the sealed brew circuit. The expansion valve is directly connected to the boiler, whatever pressure is experienced by the coffee, the same pressure is seen by 1, 2 and 4. The other numbered components take no part in this. The component under the autofill solenoid (3) is what does the steam preinfusion and incidently takes part in the clever way the machine does hot water. This component can't have any impact as it still only feeds into the same sealed brew circuit controlled by the expansion valve. This means any thermal expansion of water would be controlled ultimately by the expansion valve. My only possible conclusion is perhaps a shock wave caused by any slight airspace and water hammer due to closing of valves? **Perhaps someone could try switching of bloom phase and steam preinfusion, just have a straight shot…then see if it happens** [upl-image-preview url=//i.imgur.com/B9miMjc.jpeg]

Do you mean turn off the steam boiler or just not have any preinfusion? If so I got it just now with just a stright shot, no 10 second bloom, just 8.5 bars. It still spiked up to about 10 bars and the second shot rose to 8.5 and stopped.

> @"Del_UK"#p1323 Do you mean turn off the steam boiler or just not have any preinfusion? If so I got it just now with just a stright shot, no 10 second bloom, just 8.5 bars. It still spiked up to about 10 bars and the second shot rose to 8.5 and stopped. Everything off, probably even steam boiler (even though it shouldn't matter)…but certainly both preinfusion functions (one is referred to as bloom phase). Effectively turning it into a dumb machine. If it still does it, more evidence for a water hammer effect due to air…well that's the theory. ***P.S. If you turn off steam boiler…wait until it's below 100C***

Thanks for all the continued feedback and interesting information, everyone. Also glad (sort of) to hear I'm not alone. DavecUK, this happens even when using no preinfusion of any kind, and also with steam boiler off and cool.

I will keep an eye on mine. I never noticed this. But then again, I only have one coffee in the morning, and one in the afternoon. If there’s any testing I could do, please just let me know. 👍

@"Pygmalion"#p1333 If that is the case, I can only assume it must be a transient water hammer effect type of thing due to air? I would expect it to have no impact on the shot. Any chance of video of it doing it?

Lelit Elizabeth pressure spiking/inconsistent

Pygmalion

Thanks for running the experiment, @MediumRoastSteam ! Glad yours is working normally.

I tried the experiment with the blind basket initially full of water, and the behavior was still there with no notable change except for attaining pressure sooner, as expected.

I have opened a ticket both with my reseller and Lelit directly, to see if they can assist. But in the meantime, if anyone else has any theories I’d love to hear them.

MediumRoastSteam

Pygmalion out of curiosity, what water do you guys feed your machine with?

Ando

Pygmalion I think I have the same issue as yourself. When I run first cycle with blind basket it hits 11 bar before slowly falling down towards 9.

Subsequent cycles go straight to 9 and hold. I tried filling the basket with cold water and that one goes straight to 9 bar and holds there.

I will pay attention to tomorrow mornings shots to see what is happening with coffee in the basket. I never look at the needle - watch start of shot then fill my milk jug whilst it’s pouring.

JahLaza

Reduced it to 9.5bar with blind filter (yes it was a very easy action!) just pulled a shot, it still went up to 10.5 bar at start of shot but maintained about 9.5 bar from about 13 secs. Tastes great, not sure if there’s a difference, fuller body I think maybe. Apologies if I’ve slightly diverged from the thread topic folks, interesting all the same🤔

Pygmalion

@MediumRoastSteam I use self-made remineralized water. It is 70/30 water: distilled water with a tiny bit of baking soda and Epsom salts added according to the recipe here:
https://s3-ap-southeast-2.amazonaws.com/hosted.fivesenses.com.au/hosted_docs/water_recipe.pdf

Interesting results, @Ando . It seems like your behaves normally when the blind basket initially contains water, though, while mine didn’t behave any differently in that scenario.

Ando

Pygmalion If I leave my machine for a while, fill blind basket with cold water - it overshoots to between 10 - 11 and slowly drops from there.

Everything following this first one goes straight to 9 and stays there.

If this is normal then grand. But it does seem very similar to what your videos were showing

Pygmalion

Ah, I see @Ando - I misunderstood. Sounds like yours is behaving similar to mine then.

I also am ok with all this if it is normal and isn’t affecting the coffee. But, it doesn’t sound like it is especially normal, given that at least @MediumRoastSteam’s machine doesn’t seem to do this. I also worry that, since it definitely does this for me with coffee too, my initial shot of the day will end up being significantly different than subsequent shots, given that it will be at notably higher pressure than the others. Also, if it is indicative of some sort of flaw in the machine, then that just means a potentially more likely failure down the road, which I’d like to fix now while under warranty.

Ando

Curiosity got the better of me and turned machine back on to pull couple of shots with coffee.

First one touches 10.5 bar when machine ramps up (no PI) and is just under 9 at the end of the shot.

Second shot made straight after only goes to 9 before beginning to drop down to 8 by end of shot. This was 2 secs slower than first one.

So consistent with what was happening with blind basket tests.

Something to be concerned about?

I do struggle to dial in a lot of the time and get consistent shots that take same time etc.. I always just put it down to my inexperience or some other reason however …

JahLaza

After reducing opv to give 9.5 bar in blind basket yesterday, I pulled first shot this morning, it went up just past 11 bar and then back to 9.5/10 bar during shot. I adjusted the opv again to give 9.5 bar using blind basket. Pulled a shot of coffee it shot to 10 bar then finished out around 9/just over 9 bar. Could it be these OPVs loose their adjustment? I’m no authority on them but looks like something like that maybe in this case? Not hugely upset the coffee is great but as others have stated if there’s a defect/sign of defect it’s still in warranty!

DavecUK

JahLaza When the machine is cold and unplugged. Take pipe off expansion valve, and split expansion valve by undoing it as if you are lowering the pressure… note how many turns. Don’t remove the expansion valve from the machine.

Remove bits inside in order….so you know how they go back. Then photograph (best quality you can), post photo here. Photo both sides of the pad bit.

If it’s a bit like this photo, lubricate the metal part of the disk with the rubber pad, and of course the top o ring before replacement, tighten up the same number of turns, then check the pressure.

JahLaza

Should get to it later today what lube would you suggest (I don’t have any molycoate or similar I can pick something up today)?

DavecUK

Plumbers silicone grease…as this is only a test, one I can’t actually do. Molykote 111 would be the ideal.

JahLaza

@DavecUK Couldn’t get any molykote but got some silicone grease. Before I open it, is it at these 2 points I should lubricate?

DavecUK

Yes, those points.

JahLaza

Ok,opened, got end piece off and spring, doesn’t really look possible to get at the rest of the valve without either removing or something else. What do you suggest?

JahLaza

Got the flange piece out looks calcified to be honest

DavecUK

JahLaza Decalcify and lubricate it young man, get it nice and clean!

Then see how she goes.

JahLaza

Yep did that, she’s on the way back down from heat up now then will blind basket to adjust and then pull a shot. Only worry is I may need to take apart again if the fl^^^^ (forum didn’t allow this word last time!) didn’t sit in correctly. I’ve only used osmio zero in this machine by the way…

DavecUK

Be interested to know if the issue goes away!

JahLaza

So, success I think. I adjusted back to 9.5 bar with blind basket. Pulled a shot and it went to 9.5, falling to 9 during the shot, which I think is bang on? The OPV required about 6 extra semi turns to get it to this same pressure than when removing. Do you think the fl^^^^ is seated ok inside? Would I know if it wasn’t?

DavecUK

JahLaza Yup I think it’s all good and is confirming my suspicions shared with @MediumRoastSteam a few days ago. We just need anyone else with the problem to repeat what you have just done and confirm it fixes the problem (and post photos like you did, well non-blurry ones)..

P.S. Get some Molykote…because the silicon won’t last as long

Then I need to have a word with the owner of Lelit, once I’m sure I know what I’m talking about.

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