La Cimbali M26 - Hot water/ filling boiler problem

[Restaurator]

Hi,
I have a problem with La Cimbali M 26 machine.
When I use the hot water program, it comes frome the spout, in the same time, water pump starts working to refill the water in boiler, it stops when I finish pouring hot water. The problem is that the amount of water refilled is bigger then the amount of water used, and sometimes machine needs to pour it throu safety valeve becouse the boiler gets overfilled. It looks slike the solenoid valve (EVC valve) for water filling is open the whole time (when I get hot water). When I use coffee programe it closes corectly. What might be the case?

 

[cimbaliespresso]

When you use the coffee program the machine does not use boiler (steam) water. It uses line water that gets routed through the heat exchanger. The brewing water never gets mixed with the boiler water. Therefore, the boiler will not have to fill after brewing coffee.
The level of the boiler water is sensed by a level probe. On the M26 the probr is located on top of the boiler, on older Cimbali machines it is located on the side, above the heating element.
You can identify the probe by the two wires that go to it (older machines have one wire). One is ground, the other is the probe wire itself. Check if the ground wire has come lose. If both probe wires are tight, take out the probe and clean it with sandpaper.
Boiler overfilling is often caused by a calcified probe. The more you use the hot water feature, the faster the probe will calcify (unless you have a water softener). This will cause boiler overfilling. With heavy hot water use the probe may have to be cleaned as often as every two to three months. Personally I stopped using the hot water feature eventually. because I got tired of cleaning the probe.