Gudday!
I'm new to this forum and found it whilst troubleshooting.
I have a M31 La Cimbali, the issue is that only steam is coming out from left side group head.
Hot water is flowing properly from the right hand side.
Has anyone experienced this before and if so what is the remedy?
Does anyone have a pdf manual they can send me?
Thanks in advance, Nicko.

Hello:

hypno13 wrote: I'm new to this forum ...

Welcome. =-)

hypno13 wrote: ... only steam is coming out from left side group head.
Hot water is flowing properly from the right hand side.

Here's a snip from a D/1 manual (ca. 2000 Cimbali Junior) - There are a few manuals stored in the HB site, do a search and they'll come up.
Can't recall the link.



I think that the basics are the same in both machines: pressing the brew button pumps water through the HX (where it gets to brew temperature) and then into the group.

Since the issue is with only one of the groups and you are only getting steam and not water at brew temperature, my guess is that the problem has to do with the immediate water path to that group's HX. ie: the water path is blocked in the tubes or at the valve (Ec).

What must be happening is that the small amount of water that goes into the HX gets supeheated fast and thus flows out the brewhead as steam.

A good clean up of the tubes and valves will get things working again.

Cheers,

CIV

Yes, examining that diagram, I'd say you are probably spot on.
I'll strip it down and examine the valve and paths.
Many thanks!

Ok, here's where I'm at now....
Replaced Solenoid valve and coil.
Cleared calcium obstruction to impeller jet flow meter.
-Group came to life and delivered water pressure.
A high frequency noise was apparent when in operation.
Noise disappeared when other group was activated.
Other group developed the same noise.
Checked delivery pipe jet and filters. Cleaned replaced.
Reassembled and now the original problem of no water delivery to LH group head has reappeared!
Swapped valves and solenoid coils- left to right, to no avail.
Rechecked flow to flow impeller, to no avail.
When LH group is activated it pops loudly and the exhaust pipe sprays a bit of water.
The RH head works perfectly.

This is starting to do my head in....any suggestions?

Hello:
Welcome back ...
I thought you had given up.

hypno13 wrote: When LH group is activated it pops loudly and the exhaust pipe sprays a bit of water.
The RH head works perfectly.

The loud 'pop' you are hearing + the spray of water you are seeing are from the release of pressure of the three way valve (see Ec in the diagram I posted before).

Now, this usually happens with a loaded portafilter and after you have pulled your shot, when the water pump stops and the three way valve switches over to relieve the pressure that has built up inside the portafilter due to the resistance of the wet puck, enabling you to pull another shot without getting sprayed with hot water and coffee grounds when you unlock the PF.

Now, since the PF is empty, what you are seeing is the effect of pressure built up elsewhere ie: not between the puck surface and the valve but somewhere between the two red circles in the diagram below.

But like I said before, since you are only getting steam, the problem has to do with the immediate water path to the group's HX (blue circle).



Unless someone has a better suggestion, I'd disassemble the group from the boiler and check the plastic tube inside the HX, cleaning it up and replacing HX tube and boiler to group seals for maintenance sake.

---
Edit: in the paragraph above I'm referring to the seals for the HX tube and group. While the HX tube itself and the plastic tube inside it can be replaced I doubt they are in bad shape, my guess is that the HX tube has deposits and the plastic tube is probably just clogged.

Soaking it all in some hot white vinegar (or citric acid solution) will do the trick nicely.
---

It would probably be a good idea to do the same in both groups while you are at it.

Cheers,

CIV

Thanks again!
I'll disassemble and check those paths.
There is no steam or water coming from the LH group side.

Hello:

hypno13 wrote:Thanks again!

You're welcome.
Please check the 'Edit:' in my previous post.

hypno13 wrote: I'll disassemble and check those paths.

If I recall correctly, there's a spec to tightening the bolts on the group at reassembly time, both with respect to sequence and torque.
And then there's the re-tightening procedure after bringing the machine to service pressure, checking for leaks and letting it idle for an hour or two.

I'd expect an upper right-lower left-upper left -lower right sequence (or an inverted version) to be adequate but the torque is another matter altogether. Not enough and it will not seal properly, too much and you risk seriously damaging something.

Believe me, I'm sure it's all somewhere here at HB.
Do check it all out before doing it. =-)

Cheers,

CIV