Howdy folks,

I've got a La Cimbali Junior machine that's giving me intermittent issues with the doser. The machine is an older model with the dosing device that uses the rods at different levels. It's permanently plumbed in and has a vibratory pump.

The issue is that sometimes (seems like about half of the time) the doser doesn't stop - it will just keep on going even after the reservoir for the dosing device is empty. I've been managing by manually stopping the shot at what I guess is the appropriate time (I do this by turning the machine off and then on again). I can almost get by like this, but sometimes the dosing reservoir doesn't refill when the machine is turned back on, which can lead to the reservoir emptying and the pump sucking air (which makes a pretty nasty noise). This is a new problem, things had worked fine for 6+ months of operation.

Has anyone seen this before? I checked for the obvious loose connections on the filling solenoid and on the dosing device rods, but all seems fine. I haven't checked any of the wiring or connections at the actual toggle switches, as these seem a little more difficult to access with the machine in place.

As a side note: I've read that I should be able to manually stop a shot by toggling the selector switch, instead of turning the machine off - this does not seem to work for my machine. I've also determined that my vacuum breaker needs servicing/replacement, though as far as I know this only affects when I start up the machine from cold.

I'd appreciate any advice.

Cheers,
Andrew

Hello:

Mandrew wrote: ... Cimbali Junior machine ...
... dosing device that uses the rods at different levels.
... sometimes (seems like about half of the time) the doser doesn't stop ...
... sometimes the dosing reservoir doesn't refill when the machine is turned back on ...

All this is governed by the Gicar box located underneath the drip tray, under a metal plate held on by a screw with an allen head.
The basics of how it works has to do with signals routed to ground via cables and stainless steel rods inside the doser reservoir to determine water levels by the Gicar box circuit by opening and closing valves.

There's a Cimbali Junior manual here somewhere (at HB) that has a schematic of how this is all connected.

EDIT:
Found the schematic I once posted.


For the doser to work properly, the stainless steel rods inside the doser reservoir have to be squeaky clean and it is usual that (with time and the type of water you use) they develop a thin calcium deposit that does not allow proper conduction of the signal to the Gicar box as it acts as an insulator.

The (2) most important rods are the ones that control max level and min level, they are the ones (the shortest and the longest) that will keep the doser level in check, starting and stopping the fill when needed and preventing it from overflowing or running on empty.

The other (4) rods have to do with the level corresponding to each of the four settings on the front panel.

So what you can do is this:

1.
make a note of the place the rods are and most important, which *cable* that goes to which *rod*.
the cables have hard to see numbers on them so it is a good thing to label them.
best thing is to do this one by one so as not yo mix things up.

2.
clean them with a thin grain steel wool till they are shiny, do not forget to do the end in contact with the water.
rinse them in hot white vinegar or some other suitable solution.

Once put back together things should work properly.

Mandrew wrote: ... obvious loose connections on the filling solenoid and on the dosing device rods, but all seems fine.

This is a second step, connections and cables should be checked for end to end continuity with a reliable tester.
A bit more complicated.

Mandrew wrote: ... should be able to manually stop a shot by toggling the selector switch, instead of turning the machine off - this does not seem to work ...

This is a telltale sign of calcium deposits in one or more of the rods.

Mandrew wrote: ... vacuum breaker needs servicing/replacement, though as far as I know this only affects when I start up the machine from cold.

Take it out and apart.
Then give it a thorough wash with hot white vinegar.
You may have to change the 'O' ring, use a silicone one for replacement.

Cheers.

CIV

Thanks, Civ, for the quick reply and detailed advice. I cleaned out the rods as you recommended and tightened a few loose connections under the drip tray, and things seem to be working a lot more reliably. Still doesn't stop 100% of the time, but much better.

Hello:

Mandrew wrote:Thanks, Civ ...

You're welcome.

Mandrew wrote: ... cleaned out the rods ...
... tightened a few loose connections ...
... seem to be working a lot more reliably.
... doesn't stop 100% of the time ...

See if you can isolate in which specific situation it does not work properly.

Most of the time it is due to an issue with the Gicar not getting the signal and of these, practically all are usually related to dirty rods.
At least in my experience with a machine such as yours.

If it is not a dirty rod/bad contact, then the Gicar has to be taken out and tested.

Cheers.

CIV