Lelit Elizabeth PID temp stability

gobucks

Hello, I recently purchased a Lelit Elizabeth machine, and I’m noticing a strange issue with boiler temperature. This is my first machine, so I don’t have much reference as to how a PID is supposed to manage temps, but I was under the impression that it should make continual adjustments to keep the temp within a narrow band of the set temp. My unit seems to be behaving quite differently - sometimes it will appear to be doing this, for example, if I have it set to 93c, it will briefly dip to 92 or 91, then bump back up till it hits maybe 94, and so on; however, quite frequently I notice the temp dropping all the way down to 83-84 during idling before the boiler kicks back on and brings it all the way back up to 93+. It seems to happen whether I’m using the default LCC settings, or Dave Corbey’s adjusted settings. Is this normal? If not, is there any adjustment that can make the boiler kick on more aggressively, or did I just get a lemon that needs to be exchanged? It seems to me that the PID algorithm should be able to figure out it needs to run the boiler before it hits 9c off target.

MediumRoastSteam

Hello! No, this is not normal.

Have you switched off standby?

Could you please tell - with a video - every single value in the advanced settings?

Thanks!

DavecUK

Is the machine fully warm when you get this behaviour e.g. is it still doing it after 1 hour on?

gobucks

DavecUK Yes it is doing it after 15 minutes, 1 hour, etc. How long SHOULD the machine be able to keep a stable (say, +/- 1c) temp?

gobucks

Thanks. Yes, I have turned off standby mode, and yes, this is well after the machine has been on for over an hour. I leave my machine turned on all day, attached to a smart surge protector, and have been checking on it randomly. About ¾ of the time when I check, it is within a degree of the target temp, and I often see it bumping up or down slightly (I assume this means the PID is properly stabilizing), the other ¼ of the time, it will be off by several degrees, and every time this happens, it continues to slowly fall until it hits around 83c, and then goes back up.

I tried to upload a video showing the settings but if I compress it down to fit within the size limit, the text is unreadable. My values are: KPc 0.2, KIc 0.07, KDc 10, Bc 30, KPs 2.0, KIs 0.0, KDs 0.0, Bs 1, EC 10, ES 0, F01 0, TR1 1, TOT n/a, BLS1 3, BLS2 3, BLP1 5, BLP2 5, PRG 6.

The issue seems to still be a problem even after doing a factory reset to default LCC settings.

Could you tell me how the temperature is SUPPOSED to behave while the machine is idle (say 30+ minutes after pulling a shot, with eco mode off)? Does your machine stay exactly at the set temperature? Does it fluctuate +/- a degree or 2? Does it dip several degrees and then come back up?

MediumRoastSteam

gobucks Does it fluctuate +/- a degree or 2

Yes.

gobucks Does it dip several degrees and then come back up?

Only after pulling a shot or if you turn the steam boiler on from cold.

gobucks

I spoke to the seller of the unit, he said that these types of units are not really designed to be left on all day, and if they are left on, they will eventually start to drop the temp. Is this accurate? Is the problem that I’m leaving the unit on too long, or should the temp be stable for hours on end?

MediumRoastSteam

gobucks and if they are left on, they will eventually start to drop the temp.

I’d ask your retailer to explain how on earth this is possible. Most likely they haven’t got a clue what they are talking about and are just making an excuse to avert dealing with the issue if there’s one. Maybe the components get tired and “drop the ball” eventually? Maybe the algorithm only works for 10 minutes? Crickey. 🤦‍♂️

The temperature is controlled by means of a temp sensor and a PID algorithm. Providing its tuned well, it will keep the temperature at the set target by increasing heat when it drops below a certain threshold. It will then overshoot slightly, and try to correct itself until it gets there. There’s more to it, of course. I linked an article.

https://en.wikipedia.org/wiki/PID_controller

The only possibility I can think of is that your PID parameters are so badly tuned that it errors so much that eventually (after 15 minutes) it gets itself into some sort of irrecoverable state. But then you’d see other crazy symptoms, like overshooting quite a bit. And you tried two set of parameters, all leading to the same outcome.

In over 1.5 years of ownership, I never noticed such a thing. Granted I usually turn the machine off after I made a coffee, but there are times when I leave it on for longer too.

But I might be wrong. Maybe Dave knows something I’m totally unaware of with that machine.

DavecUK

gobucks I spoke to the seller of the unit, he said that these types of units are not really designed to be left on all day, and if they are left on, they will eventually start to drop the temp. Is this accurate?

No, it’s BS

drdre89 Is it just me or are there alot of Lelit quality issue problems people are posting on this forum with new Lelit machines. Is this why ‘Whole Latte Love’ don’t stock Lelit due to quality / reliability? …

I mean their machines have all the great features, but reliability is questionable.

Lelit sell a lot of machines, the other problem is sometimes the customers don’t fully appreciate how the machine is working/should be used. This is because the machines are well priced and rich features. For many customers it’s their first proper machine, or even their first machine. Many times the forum sees issues based around incorrect usage, use of pre ground coffee, inadequate grinders, poor water etc..

This is not to say there are not sometimes issues, Covid really hasn’t helped with component reliability, but they are not as widespread as you might think on % terms. In terms of Whole Latte love, I don’t know, but usually retailers who don’t stock a particular machine, give reasons…how accurate those reasons are I don’t know.

The other thing to consider is…customer buy machine, totally happy…doesn’t say anything. Customers with problems have a tendency to want to post about it somewhere, either to get it fixed or to let other people know…it’s human nature. I think it would look quite different if all the people completely happy with their machine posted how much they like it…human nature being what it is…that often doesn’t happen.

One thing that’s clear, Lelit definitely care and take some trouble to do all the insider videos, possibly because they realise it’s a customers first machine.

The thing to remember is; prosumer machines from all manufacturers tend to be made with similar generic components and all have the same potential for issues. The LCC (made by Gicar, the little oled display) is a components that mainly Lelit seems to use, it contains a 64 bit risc chip, is very powerful and can run a lot of complex functions. It seems to be hugely reliable. So I’m surprised other manufacturers don’t use them, perhaps because they are not cheap.

drdre89

Is it just me or are there alot of Lelit quality issue problems people are posting on this forum with new Lelit machines. Is this why ‘Whole Latte Love’ don’t stock Lelit due to quality / reliability? …

I mean their machines have all the great features, but reliability is questionable.

JahLaza

I’ve had mine about 8 months and not experienced this. It comes on at 6:30am on a timer and is mostly left on constantly until 3:30pm. This is every day. The temperature is always at the target temperature except immediately after a shot, whereby it takes a minute or less to recover. If I turn the steam boiler on after being in eco mode for example, the group temperature will drop a couple degrees but again will re stabilise in a minute or so. Lately I’ve been turning the machine off in between coffees and it just takes a few minutes to stabilise at target temp. I’ve used Dave Corbys parameters from the start. @drdre89, yes I’ve had a couple of issues from new but nothing to worry much about except the opv overshoot. All my issues were resolved with help from @MediumRoastSteam and @DavecUK. Retailers/Lelit…. Not so much!! I would have to question Lelit’s QC but all in all it’s a great machine really - when it works as it should

gobucks

DavecUK Yeah this definitely describes me - it’s my first machine, I want to make sure I didn’t get a lemon, but also I don’t really know very much so I’m trying to remember that a lot of this might be user error and/or misunderstanding. If I did get a lemon, though, I need to know what I’m talking about if I demand a replacement.

One thing I’m wondering is if it has anything to do with it being a 110v machine and/or being limited by the surge protector. The total wattage of the brew and steam boilers is more than can be supplied by a single 15A 110v outlet, so I’m starting to wonder if maybe what I’m seeing is the brew boiler temp dropping while the machine focuses on reheating the steam boiler. I did start up the machine this morning, it heated up pretty quickly and seemed to be holding temp pretty well for at least 20-30 mins, including coming back up to temp within a minute or so of pulling a shot, and then i shut it off. Considering it heats up pretty quickly, maybe there is something to be said for just letting the machine go into standby/power off when not in use, and letting it come up to temp when I need it.

On a related note, does anyone have a recommendation for steam boiler temps? I had it maxed out, figuring the increased pressure might be good for steaming drinks as well as providing stronger preinfusion, but maybe I’d have better luck if I set it to something a bit lower? (I think the default is 135c)

drdre89

DavecUK Have a look on YouTube for the Whole Latte Love “Lelit Bianca vs Profitec Pro 700” video. Marc absolutely rips into Lelit for quality issues and why they don’t stock Lelit.

They had to turn comments Off on the video because I imagine they were getting alot of hate comments. 😄

As I said I want to love Lelit, as their machines have great features for a reasonable price… but I’m not convinced the quality is there up to the level of other machines. This is something they need to improve on.

For instance people were complaining about the Elizabeth OPV overshoot issue back from March 2021 and were complaining to their retailers about it. Yet Lelit haven’t done anything about it … is this the retailer’s fault for not reporting? .. or is this Lelits fault … who knows? … I kicked up a stink with my retailer about it in hoping that it will get reported back to Lelit in order to get the issue fixed. Just one example.

MediumRoastSteam

gobucks I’m starting to wonder if maybe what I’m seeing is the brew boiler temp dropping while the machine focuses on reheating the steam boiler.

If this is something you observe frequently, then the obvious way to rule this out is to keep the machine in Eco mode (i.e.: steam boiler off) when idling. If you still experience this, than it’s unrelated. If you stop seeing this, then you are following a good lead.

gobucks does anyone have a recommendation for steam boiler temps?

I run mine at 140C.

DavecUK

gobucks One thing I’m wondering is if it has anything to do with it being a 110v machine and/or being limited by the surge protector. The total wattage of the brew and steam boilers is more than can be supplied by a single 15A 110v outlet, so I’m starting to wonder if maybe what I’m seeing is the brew boiler temp dropping while the machine focuses on reheating the steam boiler.

I think that is quite likely….I only tested the UK model which really isn’t affected, but the US model could well be….good catch on that one, I should have thought of it. Or at least thought about asking you if you were in tbhe USA.

I’d still recommend you use my settings but take @MediumRoastSteam advice about turning the steam boiler off!

MediumRoastSteam

gobucks - PS - the Elizabeth does not run both boilers in parallel. Therefore, it will always be one or the other.

According to Clive Coffee, the brew boiler is rated 1200W whereas the steam boiler is rated 1000W.

That’s 11A and 9A approx. respectively.

MediumRoastSteam

gobucks One thing I’m wondering is if it has anything to do with it being a 110v machine and/or being limited by the surge protector

Out of curiosity, why do you think the surge protector has a part to play in this? I’m assuming the surge protector is external to the machine and not something built into the machine?

gobucks

I ran the unit in eco mode with the steam boiler disabled, and it did seem to have a more stable temp. I haven’t sat there staring at it all day, but every time I’ve walked by since I turned the machine on about an hour ago, it’s at 92-93 (set at 93). I’m not sure if the issue is the limited US power outlets, or the smart switch I’m using, or if I am stressing the system by running my steam boiler too hot, but it definitely seems to have something to do with power management.

If it indeed turns out that the machine is being limited by power availability in the US, I will be somewhat annoyed that I chose a dual boiler over a HX machine like the Mara X, but on the other hand I can probably work around it, and I’d be happy if the unit is not defective. Does anyone know if it’s possible to buy a 20A cable to give some extra juice to the machine? I have 20A hookups in my kitchen.

DavecUK

gobucks Does anyone know if it’s possible to buy a 20A cable to give some extra juice to the machine? I have 20A hookups in my kitchen.

I can’t remember if the Lelit is hard or soft coded for the USA, but even if you had a 20A outlet, it depends whether the wiring in the machine can support simultaneous operation. The one bit of good news is it won’t affect the temp much, it will still average out between the two readings assuming they swing equally.

gobucks

MediumRoastSteam my thinking was that it could be delivering less than 100% of the power from the outlet to the unit. It’s a 3 outlet smart plug (TPLink Kasa KP303), so I was thinking maybe it doesn’t deliver the whole outlet’s power to a single outlet. This seems less likely than the scenario that the outlet is is simply power limited, but it was something I thought of as a possible issue.

MediumRoastSteam

gobucks - understood. What about if you connect the machine directly to the power outlet without the TPLink plug? Do you experience the same?

MediumRoastSteam

DavecUK depends whether the wiring in the machine can support simultaneous operation

My understanding is the Elizabeth does not support simultaneous operations.