Hi Guys,
I have a 2 group Cimbali M21 Plus, and its just started running into an overpressure problem.
My pressure gauge has never really worked properly and it now seems completely broken. I really should have fixed it long before now, but I haven't, and here we are. For that reason, I am not 100% certain the boiler is actually getting overpressure, but im about 95% sure that it is.
So basically, it turns on and starts to heat up as normal, and when it gets up to temp, the anti-vac valve closes and pressure starts to build, but after a while instead of just stabilising as normal, the boiler safey valve eventually starts to triger. It just sounds like a slow leak at first (and when i first heard it, i thought it was a leak and couldnt tell where it was coming from), but after a while it comes clear its venting out of the safety valve.
I have tried:-
1. Cleaning the autofill level probe (as a I read lots of people blaming overfilling for this issue) and even put a slightly sharper bend on it so it fills less.
2. Pulled out and cleaned (but did not replace) the water inlet solenoid and valve (i tested the solenoid by measuring resistance between the two pins and it showed some, i dont recall how much, but the article i read said that as long as it was not 0 or infinity, it was probably not the culprit)
3. Pulled out and cleaned and checked the operation of the pressure stat (and it seemed fine). Its one of the old Cimbali branded ones with a spring, like this: https://www.eunasa.com/en/article/vi...0_5bar_1_45bar
I cannot say for certain whether the pressurestat is clicking off or not, because once the anti-vac valve closes, i tend to move away to a safe distance just in case *this time* the safety valve fails. But what I can say is this:
1. when the machine is off and cold, the circuit is closed between the two pins on top of the pressure stat, as well as where both those wires (one whiite, one purple) plug into the control board.
2. When i manually lever the pressure stat "open", i hear the switch click, and there is no longer continuity between the two pins at the top, or the two wires at the control board (though there is continuity between each wire still (obviously).
So the pressurestat seems to operate as normal when everything is off. I cannot say for certain that the circuit is opening due to the boiler pressure or not, but i am ALMOST certain that it is. To my eyes, it looks like the angle of the lever is much higher than is needed for me to open it manually when im just levering it up.
So I think I have three potential problems:
1. The pressurestat is not working, and replacing it should fix it.
2. The pressurestat is working, but for some reason the element in the boiler is not turning off; or
3. Eveything else is working, but the safety valve is triggering too early (i really dont think its this).
First of all....can anyone thinkg of what else the problem could be?
Second, if its the pressurestat that needs replacing....which of the coffeeparts pressurestats can I replace it with, because it looks different to all of them?
Third, if its not the pressurestat, what else could it be?
Thanks guys. I am at my wits end, and not sure what else to try. Given these components are all quite expensive, I was hoping to get some ideas before i just start playing Part Replacement Roulette.
Thanks in advance.
I have a 2 group Cimbali M21 Plus, and its just started running into an overpressure problem.
My pressure gauge has never really worked properly and it now seems completely broken. I really should have fixed it long before now, but I haven't, and here we are. For that reason, I am not 100% certain the boiler is actually getting overpressure, but im about 95% sure that it is.
So basically, it turns on and starts to heat up as normal, and when it gets up to temp, the anti-vac valve closes and pressure starts to build, but after a while instead of just stabilising as normal, the boiler safey valve eventually starts to triger. It just sounds like a slow leak at first (and when i first heard it, i thought it was a leak and couldnt tell where it was coming from), but after a while it comes clear its venting out of the safety valve.
I have tried:-
1. Cleaning the autofill level probe (as a I read lots of people blaming overfilling for this issue) and even put a slightly sharper bend on it so it fills less.
2. Pulled out and cleaned (but did not replace) the water inlet solenoid and valve (i tested the solenoid by measuring resistance between the two pins and it showed some, i dont recall how much, but the article i read said that as long as it was not 0 or infinity, it was probably not the culprit)
3. Pulled out and cleaned and checked the operation of the pressure stat (and it seemed fine). Its one of the old Cimbali branded ones with a spring, like this: https://www.eunasa.com/en/article/vi...0_5bar_1_45bar
I cannot say for certain whether the pressurestat is clicking off or not, because once the anti-vac valve closes, i tend to move away to a safe distance just in case *this time* the safety valve fails. But what I can say is this:
1. when the machine is off and cold, the circuit is closed between the two pins on top of the pressure stat, as well as where both those wires (one whiite, one purple) plug into the control board.
2. When i manually lever the pressure stat "open", i hear the switch click, and there is no longer continuity between the two pins at the top, or the two wires at the control board (though there is continuity between each wire still (obviously).
So the pressurestat seems to operate as normal when everything is off. I cannot say for certain that the circuit is opening due to the boiler pressure or not, but i am ALMOST certain that it is. To my eyes, it looks like the angle of the lever is much higher than is needed for me to open it manually when im just levering it up.
So I think I have three potential problems:
1. The pressurestat is not working, and replacing it should fix it.
2. The pressurestat is working, but for some reason the element in the boiler is not turning off; or
3. Eveything else is working, but the safety valve is triggering too early (i really dont think its this).
First of all....can anyone thinkg of what else the problem could be?
Second, if its the pressurestat that needs replacing....which of the coffeeparts pressurestats can I replace it with, because it looks different to all of them?
Third, if its not the pressurestat, what else could it be?
Thanks guys. I am at my wits end, and not sure what else to try. Given these components are all quite expensive, I was hoping to get some ideas before i just start playing Part Replacement Roulette.
Thanks in advance.

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