Cimbali M20 boiler continues to fill after pump stops

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cimbali_north
Posts: 2
Joined: 12 years ago

#1: Post by cimbali_north »

Hello everyone

I'm presently restoring a single-group Cimbali M20, and I finally have it hooked up on my bench. I seem to have things ALMOST working. I have cleaned and descaled everything. The fill sensor appears to be working fine and the machine autofills to the correct level and heats up fine when the pumps is connected to a water jug. However, when connected to mains water, the boiler continues to fill after the pump stops. Is there a solenoid on the mains line that should also shut off when the pump stops, or am I missing a pressure adjustment somewhere? Or am I wrong entirely? My first restoration, so any advice greatly appreciated.

Many thanks

Alex

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cannonfodder
Team HB
Posts: 10497
Joined: 19 years ago

#2: Post by cannonfodder »

Could be a couple of things. I believe that machine also has a manual fill valve based on a few photos but I have not used it personally so that is just a guess. There is a manual boiler fill on the front of the machine that you push or twist to open the fill path. That could be stuck open. There is also a fill solenoid controlled by the glicer box (again assuming, have not used that machine). If you open the machine up and follow the water supply line it should be obvious. There will be a T that goes to the boiler/heat exchanger with a big block with electric wires going to it. That is the solenoid. It could also be stuck open. Now worst case, your fill valves are just fine and your heat exchanger is ruptured but that is an easy one to test. With the boiler if full, put a portafilter with a blind basket on it, turn on the brew and watch the boiler pressure/water level. If it spikes up you have a ruptured heat exchanger (assuming you check the other two options and they prove to be good). If that is the case you have major work ahead of you, or a fancy door stop for the kitchen.
Dave Stephens

cimbali_north (original poster)
Posts: 2
Joined: 12 years ago

#3: Post by cimbali_north (original poster) »

Many thanks Dave! That's a great help! I'll be having a go at your suggestions this weekend!

Alex

activ
Posts: 5
Joined: 12 years ago

#4: Post by activ »

Hi guys, sorry to have my first post be an answer and not an introduction (Will do that asap).

I have a La Cimbali Junior d myself and and seeing that the problem only exists when you have line pressure it seems most likely that the valve is not closing and stopping line pressure from filling the boiler.
It might help to know that as far as I know none of the models that have auto fill also have a manual fill.

Don't know which exact model you have, but if you need a manual for an old style Junior I've got a pdf for you.