Rancilio Z11 Omnicron II - Rebuild

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

Postby IanB22 » Feb 23, 2015, 2:01 pm

Just picked up my first rebuild project. A non-working Rancilio Z11 Omnicron II.
The following threads look like they will be of some use.

Please help power a Rancilio Z11
Rancilio Z11 Rebuild

I'll have some photo's up tonight when I get home, but all and all, it doesn't look to bad.

The good things is that it 'was working' about 2 months ago in a retail shop, but then died due to an electrical 'spark' according to the previous owner. Now it just trips the breaker whenever it is turned on (probably a ground-fault somewhere). It appears the unit hasn't been frozen (since I picked it up from the shop, and the shop hasn't been below freezing). And the boiler is holding some reserve water that I need to drain, but at least it doesn't leak with the water that's left in it, it the machine.

Now, the inside of the boiler is probably in BAD shape, even though the previous owner said it was 'cleaned regularly' I doubt it was fully re-furbished then cleaned regularly, so the boiler is probably in some really bad shape. Also a few spot-leaks have produced some crystal-rock looking mountains on two of the connections going into the boiler.

Two quick questions now.
1. Anyone have a link to the service manual? (Rancilio's website seems to have taken down there old service manuals.)
2. Anyone have a link to a method on removing scale on a chrome boiler?

Thanks in advance.
Finally... thanks for inspiring to take on this crazy project and welcoming me to the forum!
Wouldn't have been so thrilled to try this without all of you having this wonderfully addictive CEAD disease (Coffee Equipment Acquirement Disorder)


Postby IanB22 » Feb 24, 2015, 1:37 pm

Pictures are a few hours late.
As you can see, it's in 'not bad shape' but certainly not good.

Also, i think I found the problem last night with the ground-fault.
May have been the three-position switch.
See photo's below of burnt/carbon on the connections.

Flikr Album https://www.flickr.com/photos/78318861@N08/sets/72157651020358025/

Notice the attempt at a 'repaint' of the case. I highly doubt this paint job came from the factory.



Rear View of Switch

Front View of Switch

Side View of Switch

Carbon Build up like crazy...

Cleaned all the contacts from the switch.

Notice the calcium 'mountain' I referenced earlier.

All -n- All, I am trying very hard to bring this bad boy back to life. If you want more pictures, check out the flikr album because they are over 50 so far and there will be lots lots more to keep me from screwing something up.

Any help on the previous questions would be appreciated.


Postby IanB22 » Feb 26, 2015, 12:34 pm

Well no one appears to be super interested in this rebuild, but I'll keep posting here.

I continue to strip her down, electrical, pipes, all to access the heating element.
Here is what it looked like when I took out the element for the first time.
I was actually slightly encouraged!


However, there is crud and junk in all the lines that I pull off, and I am sure if that crud got into a valve, or a pressure gauge, or any number of small diameter pipes I would have serious problems with that small sensitive electro-valve getting clogged (and it feels like these valves are absolutely everywhere on the machine...).

I have found you can NEVER have enough photo's.
So, my Flikr account is filling up, but I am only posting the highlights here to save the Home-Barista servers.

Some photo's of the Boiler and the gunk I am finding.


Postby IanB22 » Mar 02, 2015, 10:25 am

Still working on the machine.
Almost every valve and flow control on the machine needs a complete cleaning.

The only thing I am not rebuilding/taking apart at this time is the steam valves.
Both look to be in very good shape, and I am pretty sure if they need to be rebuilt, I can take them off after the initial test post-rebuild.
Also, they are the 'last stop' on the steam train in the system. If they were the first stop or attached to the boiler, I would strip them down, but being the last stop, I can always strip them down later. For now they will just get 'opened up' and put into a de-scale solution without the stainless steel wands.

This website has been very very helpful.


Postby IanB22 » Mar 05, 2015, 10:05 am

I'll be back to finish this, but some home stuff is going to distract me for now.
Thanks for anyone who is reading (which appears to be no-one) but I want to log the event for anyone trying to do this in the future.

User avatar
Team HB

Postby cannonfodder » Mar 05, 2015, 11:16 pm

Looks like the machine was serviced at some point. That looks like Teflon gasket. Could be a standard part but most have paper gaskets. The buildup is from a small leak at the gasket. As the water seeps out of the gasket it evaporates slowly building a mini stalagmite.You may want to take the heating element off and clean the mating surfaces. Hopefully if it did have a paper gasket on it someone did not scrape it off with a screwdriver and gouge the mating surfaces.
Dave Stephens


Postby IanB22 » Jul 24, 2015, 1:29 pm

Ok, so the machine got finished after the home move.
Flickr is updated with all the detailed photos.

https://www.flickr.com/photos/78318861@ ... 1020358025