Bezzera Ellisse Boiler Overfilling
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Tio Tom
- Posts: 89
- Joined: 12 years ago
I am rebuilding a Bezzera Ellisse DE single group automatic machine. I just recently got it all back together and have it set-up and working in our kitchen. The other day the boiler over-filled and water was coming out of the anti-syphon valve. I drained the boiler made sure all the electrical connections on the boiler fill valve were good. I removed the line from the boiler fill valve to the boiler and made sure that when the machine is brewing coffee no water is passing by the valve into the boiler. I also checked that the house water line pressure is not getting by the check valve at the fill valve. I made sure that both the level probes are working properly.
One thing that I am now wondering is that this particular model machine has a feature to mix cold water supplied by the pump with the hot water coming from the boiler for the hot water tap. When the button for hot water is pushed the pump comes on and supplies this cold water to a 'mixing' system that is adjusted by a needle valve. It is possible completely eliminate the hot water coming from the boiler if the valve is opened fully. I cannot see any sort of check valve or other means that would prevent this water from traveling back into the boiler when the hot water or "Tea" button is pushed. I had been experimenting with this particular feature trying to figure out how it works before the boiler over-filled. I posted some photos below without annotations it is difficult to piece them together. The supply comes up from the pump and branches to fill valve as shown in the last photo 163036. Then from the discharge side of the fill valve the small pipe going down from the tee [162955] is the supply to the mixing system for hot water. Finally, the cold water enters the mixing 'box' [163914] and then is introduced into the flow of hot water coming up from the boiler to the tap. The more that I look at it the more I am convinced that this is what over-filled the boiler but I have always been impressed with the Bezzera machines so maybe there is something that I am not seeing. Any experience with this? Thanks.
One thing that I am now wondering is that this particular model machine has a feature to mix cold water supplied by the pump with the hot water coming from the boiler for the hot water tap. When the button for hot water is pushed the pump comes on and supplies this cold water to a 'mixing' system that is adjusted by a needle valve. It is possible completely eliminate the hot water coming from the boiler if the valve is opened fully. I cannot see any sort of check valve or other means that would prevent this water from traveling back into the boiler when the hot water or "Tea" button is pushed. I had been experimenting with this particular feature trying to figure out how it works before the boiler over-filled. I posted some photos below without annotations it is difficult to piece them together. The supply comes up from the pump and branches to fill valve as shown in the last photo 163036. Then from the discharge side of the fill valve the small pipe going down from the tee [162955] is the supply to the mixing system for hot water. Finally, the cold water enters the mixing 'box' [163914] and then is introduced into the flow of hot water coming up from the boiler to the tap. The more that I look at it the more I am convinced that this is what over-filled the boiler but I have always been impressed with the Bezzera machines so maybe there is something that I am not seeing. Any experience with this? Thanks.
