tiroth Senior Member Joined: 30 Jun 2006 Posts: 7 Location: Pittsburgh Expertise: I love coffee
Espresso: Bezzera BZ40 Grinder: Mazzer Super Jolly Drip: Melitta Roaster: Poppery II
Posted Mon Feb 17, 2014, 8:05am Subject: Bezzera BZ40, clogged boiler fill solenoid?
Hi, haven't been here in a while. This forum helped me rehab a BZ40 that has been going strong for 8 years now and I might need some more help!
The pump is running continuously, and I followed the advice in the following thread and I think I narrowed it down to the boiler fill solenoid. "Bezzera BZ40"
The instructions in that thread are to take the solenoid apart and clean it; can anyone give more details on how to do that? The solenoid body turns freely under the screw/lock washer, but if I try to turn the screw (which is round and smooth) counter-clockwise it isn't budging.
Here is what I did to investigate the issue: - I am getting water to the unit because if I run the head, water comes out. - At first the boiler was trying to fill AND the safety probe was allowing the heater to engage (green and orange lights lit). If I shorted the fill probe the pump stopped and the unit started heating up (lights still lit, pressure rising). - After running the heater a bit the water level is lower and both safety and fill probes are reading empty. Both green and orange lights are out. - I think the solenoid is actuating; after the click of the main power relay I hear another click. I think there are only two solenoids in this unit so it must be the boiler fill solenoid. (?) So, the solenoid may be good but blocked by scale. - I tried to follow the advice in the thread above to disassemble the solenoid, but I may be doing it incorrectly. When I look at the solenoid the valve is at the bottom and the speed-nut assembly is at the top. The blue solenoid body turns freely on top of the valve assembly, but if I try to rotate the pin with a wrench it doesn't move a bit. I was trying to turn counter-clockwise.
SStones Senior Member Joined: 24 Nov 2012 Posts: 510 Location: Canada Expertise: Professional
Espresso: Giga 5, ECM Giotto, Rocket... Grinder: Anfim Milano-Best Vac Pot: No :( Drip: Some $30 thing from Walmart Roaster: I buy pre-roasted.
Posted Mon Feb 17, 2014, 5:34pm Subject: Re: Bezzera BZ40, clogged boiler fill solenoid?
If it looks exactly like that one in the picture, the speed-nut will pry off (And fly across the room, then become invisible). The coil (The near-cube with wires) will slide up and off the valve. Then the 4 screws (Probably 3mm allens) in the corners of the valve need to be removed and the valve is open.
Additionally, if it thinks it's full until it gets hot, it might be calcium crust built up on the probe. It makes damp contact until the boiler is hot enough for the water to evaporate out of the crust... I don't know, but check the probe anyway. One calcium issue means check the easy access points.
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