Help Identifying 1 Group Espresso Machine and Part

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

#1: Post by cmenoob »

Hi Guys,

I am trying to identify this machine I picked up (my first) and what part I need to repair it.

From searching around the internet it looks like some variation on an Astoria Junior machine, though I didn't find any exactly like it. The back plate says San Marino, but the front CMA label does not show a model number. Here are some general photos of the machine with the panels off.

So I purchased this machine from a guy who had it in his bar until it broke and he sold it to me cheap. The pump works great and this machine seems to have the auto-fill system since shortly after turning it on, the pump activates and tries to pump water into the boiler.

The problem I'm seeing right away (there may be more?) is on the left side of the boiler, there is a pipe that goes from the pump inlet tap (the one that contains the manual fill handle) to the back left side of the boiler.

On this pipe it looks like there is a fitting that is missing or broken off and when I turn on the machine, water just pumps of of this hole onto the counter.

The photo above is taken from the back with the pipe in place, coming around from the right front of the machine and finally up to the back left of the boiler.

These two photos show the pipe in question removed from the machine with the fitting in question. This is my first machine so I'm not exactly sure but from various photos it looks like there is supposed to be a pipe coming out of this hole that drains to the drain tub, is that correct?

If that's so, is it normal for water to be coming out of this immediately after starting the machine, or should it be going to the boiler instead?

Finally, where can I get a replacement for this part? Is there a valve in there?




#2: Post by RobAnybody »

i found a general CMA service manual which holds the schematics for various CMA models ... rinomanual
Interestingly, the main hydraulics system appears to be the same for the different models (except the lever version)
(the manual has a interactive index so you can click directly on hydraulic diagrams to gwt to the interesting part.)
the snapped off connection should be attached to the boiler
drain valve. here is a snapshot of the schematic:
starting at nr 5 (the manual fill valve) going to the boiler is the pipe you mention.
hope this helps!
LMWDP #647

cmenoob (original poster)

#3: Post by cmenoob (original poster) »

Thanks! Do you think the missing part is #6, the SCNR valve shown in the diagram?

It doesn't seem like that connection could have went to the boiler, since all the ports on the boiler are already occupied.



#4: Post by RobAnybody »

if i follow your description of the way the pipe was connected (coming from the manual fill valve and going to the boiler) my estimated guess would be that the broken connectiion was connected to the boiler drain tap (nr 17 in the diagram).
LMWDP #647

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#5: Post by MNate »

That seems right to me too. I often liked to look at the diagrams to see how things fit together. Models seem to share a lot in the CMA stuff so just look for what seems similar. Yours looks to be in decent shape. Hope you find things well inside.

cmenoob (original poster)

#6: Post by cmenoob (original poster) »

Well judging from where the fitting is in the diagram (right before entry to the exchanger at the left rear of the tank) this must be the 3-way back pressure relief valve shown as #6. Everything else seems to be accounted for from the diagram and there are no empty ports on the boiler.

Figuring out what valve to get seems like its going to be an issue too since I'm not even sure what this machine is exactly. For now I'm just going to cut out the fitting for the relief valve and solder in straight tubing. If I can find a source for the original tubing with the valve attached I'll end up replacing it anyway.



#7: Post by RobAnybody »

well you're the one looking at the actual machine instead of a diagram that may or may not represent the machine in question :wink:
if everything else is accounted for then it could very well be the pressure relief valve.
LMWDP #647


#8: Post by sar5w »

Just guessing because there are some things I can't see in the pictures . . . I think that would be an expansion valve that would relieve excess pressure in the brew circuit at idle and empty into the drain cup a few drips at a time. With it being broken/missing, water will flow freely under line pressure because there is nothing closing that brew circuit off. If the pump were engaged, it would gush.

Where is the flow meter? There should be one in the brew path as part of the volumetric dosing controls.

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Mad Scientist

#9: Post by Mad Scientist »

I have a CMA on the bench now. This is my pipe. On the right fits into the flow control and on the left fits into the boiler HX input.

I'm not sure what's in the middle, maybe a non return valve. The copper goes to the drain cup.


“You haven't lived until you've lived with a cat.” Doris Day


#10: Post by luvmy40 »

See part numbers 12, 13, AS233, AS234

This diagram is from espressoparts . com, CMA, Argenta