Bluenoser wrote:Is there any chance the probes have a weakness in the seal of the thermistor to the steam? I don't know how the probes are built, but if any amount of liquid gets to the thermistor is will exhibit erratic behaviour. So I wonder if those exact same probes are used by other manufacturers. I also think it could be a connection issue.. cold solder joint or the like.. but some of these are happening on newer units and usually that takes more time to occur.

What would happen if one simply dried the same probe with heat, without cleaning it.. putting it back in.. and see what happens..

I think what is needed is data as to the exact manufacturer and batch of the probes and start tracking those.. see who else is using them.. and try to find some common characteristics.

bzarycranski wrote:This thread is far from conclusive. Various water recipes have been involved/implicated, various machine manufacturers, etc. but a clear cause/effect relationship hasn't been established.

My first Elizabeth began to experience steam boiler over pressure issues within the first 48 hours of using rpavlis water. Other waters I have used include Kirkland Purified Water with minerals added for taste (with additional potassium bicarbonate added), Brita filtered tap water, etc., all with the same result on the original machine.

Jim at 1st line blamed the water immediately and asked me to clean the sensor which I did and this fixed the problem for about 72 hours but the problem returned. I took the machine to him for his evaluation over several weeks. I am not sure what waters he used at his shop but he experienced the same problems after replacing the sensor, other electronic parts and the boiler safety valve. Last i heard he was waiting for a new boiler from Lelit to place in the machine.

Since I was without a working machine for a few months at that point, Jim gave me a new machine which has worked perfectly for two months using Brita tap water and the Lelit in tank ion exchange softener. In my mind, this does not prove water was the culprit since the new machine has all new parts from various production runs, etc. any of which may actually contribute to the problem.

I am not sure what to make of a 'film' causing wild, inaccurate temperature fluctuations. What exactly is the composition of this 'film' and how does this interact with the probe - Potassium? Bicarbonate? Or some corrosive material as a result of using rpavlis water between 60 mg/l and 100 mg/l? What to make of Jim's experience with the machine at his shop as he systematically replaced several parts using whatever water he routinely uses. My machine is finally making great coffee using the in tank softener but that isn't definitive proof water caused the problem. I would nice to substitute rpavlis water now with the new machine as a rechallenge, but I am going to leave well enough alone!

I do know Jim at 1st Line solved my problem and I am a happy customer who is drinking great coffee. Hope someday the cause or causes for the interaction of various combinations of machines and waters becomes known.

elkayem wrote:If steam were able to bypass the seal and get into the probe casing, then the result could certainly be these erratic sensor readings. This could also explain a few other things, such as why removing, cleaning, and reinserting the probe resolves the issue in most cases (according to Jim), and why in some cases the problem only shows up when the machine first heats up, as reported early in this thread. In the latter case, a bad seal may only show up when the machine is cooler before the metal expands, and moisture in the probe may dry out after the machine is on for a while. If the weakness in the seal is on the boiler side, it could also explain why changing the probe didn't resolve the issue for bzaricranski and why Lelit recommended changing the boiler. This is just speculation on my part.

Here is an image of the probe. It isn't clear to me how moisture would bypass the seal and get into the probe. I assume that Teflon or some other sealant gets added to the threads. It is also possible moisture is getting in through some other path.

image

dlcain wrote:Anyone offhand know how well isolated from heat the connector to the probe is? Anyone experiencing the problem want to try a simple experiment and dab a little conductive paste on the pins/sockets to see if that has an effect?

elkayem wrote:As one of 1st-line's customer's, I truly appreciate Jim's feedback on this forum. As a reseller, they are in a unique position to see the same issues crop up time and again across multiple machines and customers (most of whom I'm sure don't post here). With this data, they may be able to draw inferences about root cause that might not be obvious just by reading posts on this forum. This is not just valuable information for us, but also the manufacturer who can correct defects like this, and I believe there is a defect here.

What is missing from this conversation is a real root cause analysis. I am encouraged to hear that Lelit has hired a water expert, and hope they are engaging other experts to find out what is behind these overpressure events as well as an appropriate corrective action. The message I've heard so far is that many (most?) of the customers encountering this issue have been using certain water formulas, and most of the time (but not all?) it can be corrected by cleaning the temperature probe and changing water. This is a strong clue at the root cause, but this cannot be the end of the story and there is still a lot of work to do here.

I can't help but relate this to my own line of work - I have spent the last few decades as an engineer in the aerospace industry - and our own industry's methods for getting at root cause through the Failure Review Board, or FRB. There are many examples familiar to the public - a failed shuttle launch due to a brittle O-ring launched on a cold Florida day, a space telescope with an optical aberration due to an incorrectly manufactured calibration tool, a Mars orbiter crashing into the red planet due to a mix-up in English vs metric units in the ground navigation software. (Aside... one of my favorite examples from TV comes from the recent miniseries Chernobyl, which unfolds like a mystery where the root cause is finally revealed as... ok I won't spoil it but do yourself a favor and watch this show.) All of these high-profile catastrophic failures were investigated with an FRB, but most FRBs are encountered during ground test, designed to find root cause and correct more innocuous-seeming issues (e.g., an electronics board which occasionally fails to reply to a command) before they turn into a billion-dollar problem. In these reviews, hypothetical root causes are laid out, often in a "fishbone" chart, and systematically ruled out until what remains, like a Sherlock Holmes case, turns out to be the true cause. The corrective action is just as important, mitigating the risk of similar problems in the future.

I'm sure Lelit does not have the resources to conduct a full aerospace-style FRB, but it sure seems in their best interest to do what they can. The repercussions of not fixing issues like this include expensive warranty headaches, lost customers, dealers deciding to drop products, damaged reputation, etc. I would propose the following questions to investigate:

• What are the observables? Clutch stated that his steam boiler temperature probe measurement was jumping erratically, perhaps between a false (low) reading and the true temperature. Are other owners seeing the same behavior, or are some different, such as a reading which is consistently low?
• What hardware do all of these cases have common? Is it the same temperature probe? Same sensor technology (e.g., same NTC thermistor and/or digital converter IC)? Same Gicar controller? How about the boiler? Same stainless-steel alloy?
• Are there any manufacturers or machines using the same parts identified above that do not suffer from this issue? If so, what is different about these machines?
• Water is a prime suspect here, but I haven't seen anything in these 9 pages of posts to draw a conclusion. Are there any ingredients in common to most of these failures (e.g., I've heard Epsom salt recipes mentioned)? If so, I also wonder if Lelit is able to reproduce the issue with the same ingredient(s) and then resolve it by removing the "film" from the probe. I also can't ignore Clutch's experience with his brand new machine and Brita filtered tap water, which does not fit the model here. It could be that his case is unique, and he has a loose electrical connection with his temperature probe.

All of this should ultimately result in a corrective action. If it is as simple as avoiding water formulas with a certain list of ingredients, that would be easy (and should get stamped as a warning on every user manual going forward). If it is traced to a style of temperature probe, then Lelit (and other manufacturers using this probe) should at least conduct a recall or extend warranty coverage to replace this specific probe when it goes bad.

I'm ending my long post here. I am quite interested to see how this resolves, as I plan on owning and enjoying my Bianca for many years.