This post is to help other Bianca owners that come to this forum in search of a resolution for Error 3.

I use a timer to power-on my machine at 6 am, and twice in one week I found the machine in error state 3. This means that it took more than 150 seconds to fill the steam boiler. I was awake the second time it happenned and I heard the pump working with the over-pressure valve stuck open and water filling the drip tray. Cycling the machine off/on cleared the error in both cases, but the fact that it occured twice in one week after two+ years of no problems had me concerned.

Upon digging into this I came across the post on particles found in water from the hot water wand (Lelit Bianca, particles forming in boiler (rpavlis water) ). This led me to conclude the following:

1.) Particles in the steam boiler are apparent when one does NOT use the hot-water wand over an extended period of time, which had been my situation. I feel this is to be expected as water and minerals in the boiler accumulate when one is only drawing steam on a regular basis.

2.) The particles may jam the over-pressure valve during a cold fill (my opinion only), or the valve is just stuck open when the machine is attempting to fill from a cold start. With the valve unable to close (for whatever reason), the water just runs out so pressure is not achieved within the 150 second limit, hence Error 3.

Also, I am at times surprised in the morning to find my machine in low-water state, so this stuck-valve problem may have occured in the past but was hidden by running out of water before the 150 second limit for error 3.

My fix, which has now been working for a month:

After making our morning coffee I now draw fresh water into the steam boiler by pulling hot water until the moment I hear the refill pump start. This has two benetifs (IMHO):

1.) The steam/hot water boiler is maintained with relatively fresh water, especially when one does this every day. Since I started doing this I no longer see particles in the pulled hot water.

2.) The boiler water volume is topped-up before cool-down so that the next day's power-up cycle does not trigger an attempt to refill the steam boiler from a cold machine. This avoids Error 3 on start-up the next day. I suspect that once the machine has warmed up, the over-pressure valve is nicely set by the pressure in the boilers.

Before the Bianca dual-boiler I owned two heat-exchanger machines (Andreja Premiums), and this experience has led me to believe that I abused both those machines in the same way as both suffered similar and untimely deaths, needing new boilers. So if I am right in my analysis here, I would also suggest the same practice for a heat-exchange machine - regularly pull hot water until the pump cycles on, and do this after completing your daily coffee ritual.

I believe your recommendation is correct, just maybe a little late. I think this has been more-or-less a "best practice" for double boilers machines for the last few years.

Thanks for the feedback and confirmation @slybarman. I guess I "missed the memo".

Never-the-less, I suggest it should be best practice for heat exchanger machines as well since the steam side of the operation would suffer the same problems if water is not drawn regularly. I confess that I also noticed particles in the drawn water from both my Andreja Premiums (heat exchanger machines), so symptoms from infrequent use were similar.