Lelit Bianca: steam element dead? Endoscope images in thread.

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
pej
Posts: 9
Joined: 4 years ago

#1: Post by pej »

My Lelit Bianca is just over 2.5 years old. This morning I made a coffee with milk and enjoyed the usual excellent steam pressure. When I went to prepare my afternoon brew, I noticed that the steam boiler had no pressure. Checked the temp on the PID and it was showing 84 degrees (set to 125) and didn't budge from there, allowing me to deduce that it was not actively heating. Perhaps an hour earlier, the RCD/safety switch for my house tripped which is unusual, and I realised that it must have been the coffee machine short circuiting.

I immediately cut the power and removed the top panel to get a look at the internals, thinking that maybe a hose had come loose or the steam boiler had somehow leaked water inside, but it all looked fine. Earlier in the day, before the power tripped, I thought I heard a 'popping' sound come from the coffee machine but dismissed it thinking the sound must have come through the open window next to it. Now I wonder if that noise was my steam element expiring.

I have a cheap endoscope that I bought off amazon that I've used to inspect my steam boiler for scale so I whipped that out and took some photos, trying to see if I could visualise any signs of the steam element being blown. It looks in pretty good condition with no visible rupture and little to no scale on the coiled part of the element or walls of the boiler, however I did notice some white crud at the very base of the element, which you can see in photos below. Does this appear to be scale? It seems odd to me that there would be so much built up here but not anywhere else. The boiler also definitely contained water - lucky the endoscope is waterproof!



In terms of other potential culprits for the boiler failing to heat, I also took out the level probe and gave it a good clean, although it wasn't particularly dirty. As I understand it, a failing level probe will prevent the boiler from heating as it will not detect any water, but I would also expect that this would cause the boiler to overfill, and this did not happen - the pump stayed off. I cleaned the temp probe too for good measure and now that the machine has cooled down, the temperature of the steam boiler is reading roughly the same as the ambient temp, so I suspect it is functional.

I have recently (about 2 months ago) replaced the anti vacuum and safety valves, so it is also not a case of pressure failing to build due to these being open. The safety switches on top of the boiler don't appear to have been activated, and I also do not smell any electrical burning or see any evidence of burnt or melted wires anywhere.

I suppose water may be relevant here - I have always used filtered tap water. According to my local water report the water is quite soft and pretty much within the desired ranges, aside from slightly higher chlorides (24.6mg/L). I'm not bothered to mix/purchase water and have accepted the risk that the supply to my home may deviate from the report.

The brew boiler seems to be working just fine and I have disabled the steam boiler for now until I can figure out what has gone wrong. The only conclusion I can draw is that the steam element is bad and needs replacing, but I wanted to jump on here to get the wisdom of the crowd before I replace it, to confirm that I haven't missed anything, so any advice would be greatly appreciated.

I've seen this thread where the OP reports a somewhat similar issue and was able to check the resistance of the offending heating elements. I don't happen to have an ohmmeter on hand but would consider buying one if it can give me a definitive answer. Very much looking forward to any advice. Thank you!

DaveC
Posts: 1775
Joined: 17 years ago

#2: Post by DaveC »

Looks like it might be an egress of the MgO insulating filler used in the heating element. Possibly the element has blown a hole in the sheath? Although an ohm meter if sensitive enough might well verify that for sure....you can also see if power is reaching the element terminals and many other things.

Usually in the UK an RCD would trip, or a fuse would blow (which yours did, but would keep tripping)....so it's unusual that this is not happening. this means it could be a red herring and something simple like a limit stat failed or popped open? Or even both things failed. A multimeter should be your next 60 USD espresso purchase...it will save you money in the long run.

pej (original poster)
Posts: 9
Joined: 4 years ago

#3: Post by pej (original poster) »

Thanks DaveC. Sounds like a multimeter to test the steam element and limit stats is a no brainer for the next step. Is there anything in particular I should consider when purchasing one for this use case? I can see they range quite significantly in price.

Ben Z.
Posts: 433
Joined: 17 years ago

#4: Post by Ben Z. »

Cheap is perfectly fine

DaveC
Posts: 1775
Joined: 17 years ago

#5: Post by DaveC »

pej wrote:Thanks DaveC. Sounds like a multimeter to test the steam element and limit stats is a no brainer for the next step. Is there anything in particular I should consider when purchasing one for this use case? I can see they range quite significantly in price.
Don't get one that's too cheap, in fact having good leads is very important. The Amazon one below looks good, or you can splash out for a Fluke 101, 106...but they probably won't be better than an amazon one. Don't get a dollar store multimeter.

https://www.amazon.co.uk/dp/B083V7N12H/

pej (original poster)
Posts: 9
Joined: 4 years ago

#6: Post by pej (original poster) »

Multimeter from Amazon arrived today and I believe that it confirms the steam element is burnt out. Both limit stats passed continuity test and read 0.3 on the 200Ω scale. Steam element did not pass continuity and I couldn't get a reading. Tested the brew boiler as a sanity check and it passed the continuity test also. I suppose the next step is to order a new steam element and follow this guide from Clive Coffee. It is a big relief to diagnose the problem and know how to proceed, so thank you, everyone!
Pics of readings below if anyone is interested:

Left limit stat


Right limit stat


Steam element (display reads "1") which indicates the element is dead (or resistance > 50Ω) according to the manual

pej (original poster)
Posts: 9
Joined: 4 years ago

#7: Post by pej (original poster) »

Just an update if anyone is interested - I've replaced the steam element and all is well.