Here is a video of the issue when it occurs. I will upload another one soon with whole warmup

Here a full Video As per lelit

our technical dept. says the machine can be used as it is for now, otherwise they suggest replacing the temperature probe of the coffee boiler (art. n. 9600092) and the thermostats (MC032)

The continuous leaking at the group drain spout seems a sign of a worn infusion valve.

Hi All. I would like to post a follow up of my issue.

After extensive discussions with Lelit about the guarantee coverage, they said I should talk to my reseller and only him can decide if he will cover it under the guarantee or not. Their suggestion was to replace the temperature probe and the two thermostats from the coffee boiler.

As the issue was appearing randomly I decided to investigate it further before arguing with my reseller about this.
My first course of action was to remote Lelit water filter and use the Soft bottled water I was using the whole time. As of then, the issue seems to be gone. I was not in front of the machine for every warm up but I was more times than usual and in any warm up I witnessed a normal start up.

I am guessing that either the filter was not good (or passed its capabilities) or that it was making the water too soft that caused the abnormal readings and issues. I will work like this for a while but I will defiantly add a new filter in the future.

Here is a photo of the water I am using

I don't think the filter is to blame. It does not remove minerals, but replaces one for the other, calcium and magnesium for sodium.

I agree.

However it's probably worth pointing out that the LeLit filter will only exchange a certain amount of hardness minerals and once that's used up it will do no softening at all. The Lelit MC747Plus 70 filter in the Bianca can soften 70 liters of water with a hardness of 200 mg/L CaCO3. (See LeLit Bianca Water Filter Advice ). The label on your pictured bottled water says that it has a hardness of 96 mg/L, so the filter would soften about 140 liters of that water before the softener is exhausted. When the filter has treated that much, or if it has been in the machine 6 months (whichever comes first) it should be replaced.

The calcium ion of that pictured bottled water is 37.4 mg/L, which translates to a calcium hardness of 93.5 mg/L as CaCO3. Most of us would call that moderately hard water, likely to cause scale deposits if you fail to soften it. Still, I doubt that this has anything to do with your problem, aptly described by JRising as 'weird antics of some Lelit sensors'.

Thank you all for your replies. You are right that the filter in general is not to blame. Probably this filter is exhausted? I am not sure when I replaced it but according to my calculations I was below (or close) the 70 liter mark and since this water is softer than 200 mg/L my use was defiantly below 140 lt. I will keep the machine without filter for a few more weeks and I will add a filter then and recheck.

Did you ever get the temp issue sorted? For some reason Lelit were fitting one 165 resettable thermostat, and one non resettable 140 thermostat to both boilers for a while, so if either boiler went over temp, the power just turned off, and came back on again once the temp went below 140.... both thermostats should be resettable 165 thermostats . It's worth noting the brew boiler logic overheats the brew boiler on initial heatup too to speed up heating.... If you can post a picture of your thermostats, we can confirm if correct

Hi Mike,
The issue disappeared as soon as I removed the Lelit water filter. I use the soft bottled water I mention above and it has been over a month of use without a single incident. I cannot be sure about the thermostat you mention because I haven't opened the machine, but if the safety thermostat was triggered I would have to open up the machine in order to reset it which was not the case. I believe Lelit has incorporated a safety feature in it's LCC that triggers the soft-power-off if they see temperatures above a specific limit. My assumption is that due to "bad water" the temperature probe was reading the temperatures wrong that is why I was having these issues. The overheating feature works very nicely if the probe detects the correct temperature. If the probe malfunctions then heatup takes a lot (above 45 minutes) as whole system is overheated. There were many times that I also experienced this issue (check video http://www.youtube.com/watch?v=uLxxow-cx-M) . If you check the comments you will see that the issue was also related to very soft water.