M2 problems

Albe

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Jan 22, 2016
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Hello all! I got my hands on a Cimbali M2 that was poorly taken care of and partially disassembled. After a complete tear down, descale, and replacement of all gaskets and flexible lines I ran into an issue I need help with. The second time I pressurized the machine, steam began leaking from the electronic pressurestat. I thought it was the two small O-rings below the circuit board, but after replacing them I realize that air is flowing freely from black plastic chamber on the bottom of the circuitboard. My assumption is that air should not escape this since it's job is measuring the pressure of the boiler. Any insight would be greatly appreciated.
 

CCafe

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Aug 11, 2004
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Des Moines, Iowa
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That black plastic piece of the pressurestat is probably shot. From time to time will split or blow out on the bottom side of that piece and blow steam and water all over the board. That board is about $300. PM me if you want to purchase one.
 

Albe

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Jan 22, 2016
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Thanks for the reply CCafe! I was able to get a replacement pressurestat from a local repair technician. $300.00 dollars later (just as you said) and I'm still having an issue. The machine starts up and heats up. When the boiler is at temp, I can dispense from the water tap and the turbosteam wand operates correctly. The machine will even produce a decent espresso (not adjusted yet). But then the OPV valve goes off and steam vents into the drip tray. It seems that the machine continues to heat up even after it is up to temp. Checked all my wiring connections and all seems snug and proper. Nothing on the display gives me any clue as to what is going on. Super frustrating!

One other last question as well. I have gone over the schematics time and time again and I cant figure out where the "Water After" circuit is supposed to dispense to. The Teflon tube currently just sits in the drip tray. I know that isn't correct. I do not have the cappuccino version of the M2. Therefore the diagram shows the tube being piped in between the brew group and dispensing head. There is no where on this machine to make that connection. It is like that connection was removed at some point. As I stated previously, the machine was in pieces when I received it and not everything was there. It began its service in an Olive Garden and has changed hands 3 times since then so your guess is most likely better than mine. Any help would be awesome!

BTW CCafe you must be a full time technician as you seem very knowledgeable about these complicated machines.

Thanks again!
Albe
 

Albe

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Jan 22, 2016
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Thanks for the reply namballe. The pressurestat on this M2 is electronic and only has a programmable variance of 0.1 bar. I did check it just to be sure though.

To to give a little more info I received error code 051. The programming manual says this is a "boiler temprature malfunctioning" code.

Thanks in in advance for any help.

Albe
 

Albe

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Jan 22, 2016
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Alright. So I dug into the manual as much as possible. Not knowing what had been programmed into the machine in the past, I decided to reload the software for the computer by turning on dip switch #1 on the main board and followed the technicians manual to get it back to factory defaults. After making a small mistake in the options and performing the data reload again the software seems to be operating as expected.

After that I used the "testing" menu to calibrate the pressurestat. After the calibration the machine said "OK" meaning that the calibration was successful.

No more error code after this. All of the features of the machine operate just fine and it produced acceptable espresso and the turbosteam wand steamed some decent late milk. I went through the "manual programming" menu and actuated each solenoid, motor, and pump in the machine and everything responded as it should. However, the machine is still over-pressurizing and the OPV valve went off again.

I'm not sure if the computer is supposed to control power to the heating element or if the probe that is attached to the heating element that goes to a physical limit switch mounted just below the left grinder is supposed to cut off the power. My guess is that the probe is just a safety switch and the computer and the pressurestat are supposed to control the boiler's heating element.

Frustrating Grrrrrr!

By the way, thanks for the response!
 
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