Help with La Pavoni Domus Bar electrical problem

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
Seafoamgreen

#1: Post by Seafoamgreen »

Hi! My La Pavoni domus bar makes my house main fuse go, after being on a few minutes. I guess its something wrong with the heater element and wanted to take it apart to have a look. Have taken off the four screws in the four corners. Whats the next step to have it apart, the two pieces are very hard stuck together. See pic. Thanks!


Seafoamgreen (original poster)

#2: Post by Seafoamgreen (original poster) »

ok I solved taking it apart. theres a tube inside holding the two pieces together, so had to be screwed off.

The boiler looked good inside, don't think thats the problem. Anyway looking at the terminals the porcelain insulation around them had cracks and was partly missing. Is that something to worry about? The picture showing how they should look like when not broken.

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JRising

#3: Post by JRising »

No, The porcelain insulators help to keep the actual conductor in the element from touching things, but on all old machines where the porcelains have cracked off years ago, the air gap is good enough.
If you have determined that the ground fault is in the element and don't see an actual burst or anything, it could be entirely hidden inside the tube. Is the resistance still normal? 20 to 40 Ohms or so?

Seafoamgreen (original poster)

#4: Post by Seafoamgreen (original poster) » replying to JRising »

Thanks!
I've got 47.8 Ohms between terminals. So guess it looks good. When the main house fuse tripped the machine had been on for a few minutes and steam switch was also on.

JRising

#5: Post by JRising »

My bet is still on "Element is shorted to ground", just because it's so much more likely than other components.

Seafoamgreen (original poster)

#6: Post by Seafoamgreen (original poster) » replying to JRising »

I replaced the element and the machine is working again. Thanks!

Seafoamgreen (original poster)

#7: Post by Seafoamgreen (original poster) »

Have a question on another fault with the machine. When building up steam, there is leakage at first from the group head. First dripping, then steaming but when steam has finished and ready tve leakage stops and I can use the steamer as usual. Leakage is only happening during build up. What can cause this?

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JRising

#8: Post by JRising »

If you just leave the machine untouched with the steam switch on, does it stop coming out the brew-head?
My guess is that it's just the water trapped in the heat exchange pipe (and that teflon tube on top of it) getting heated to above boiling temp, expanding and forcing the water below out, but it should stop once it has all evaporated. Additionally, if the three-way valve is clean, most of the water should drip away, both the showerface and drain are open to atmosphere at idle and it should flow down and out the drain into drip tray.

The scary idea is that your boiler water is actually boiling, expanding and escaping out your brew head, this will allow your boiler to boil dry and your new element will soon be destroyed like your last one.

Ask more questions or give more info about symptoms if we can advise further.

Seafoamgreen (original poster)

#9: Post by Seafoamgreen (original poster) »

JRising wrote:If you just leave the machine untouched with the steam switch on, does it stop coming out the brew-head?
Thank you so much for helping out! Yes, looks like it stops right about the same time the steam led lights up, indicating the steam is ready. I put up a video showing what it looks like!

Link:

Javierba

#10: Post by Javierba »

I would say that the water trapped in the "heat exchanger" is boiling away as the boiler gets up to temperature

Part 28 in the photo

https://cdn11.bigcommerce.com/s-4a086/p ... arts-1.jpg

What I find weird is that the vapor is venting through the group head and not through the three way valve...

Maybe is your three way valve dirty?