MarkBlack Senior Member Joined: 7 Dec 2012 Posts: 1 Location: Minnesota Expertise: I like coffee
Espresso: Rancilio Silvia Grinder: Rancilio Rocky
Posted Fri Dec 7, 2012, 2:00pm Subject: Rancilio Silvia 3-Way Valve Not Working
Some great posts on Miss Silvia, but I haven't seen an answer for this one yet. A bit of history - Miss Silvia is 9 years old and has served us extremely well. Our son is now an aspiring barista and has used Silvia to refine his technique! We have cleaned her periodically, but we hadn't taken the best care of her in the descaling department. A couple of weeks ago, my wife descaled her and got a lot of gunk out. However, afterwards flow through both the group head and the steam wand was greatly decreased and got worse over the last few days. To make a long story slightly shorter, I replaced the pump and also totally disassembled and cleaned the boiler and the 3-way valve. Now she pumps through the steam wand with great abandon, but I am not getting any flow through the group head, even though the pump is running.
It appears that the 3-way solenoid is not activating when the switch is turned on. Here is what I have found through my troubleshooting:
I have taken the solenoid out and hooked it up to household current and it does activate (is magnetic). I checked the voltages across the three legs going to the solenoid when the brew switch is on. I have 27 volts between the white and orange wires, 110 volts between the white and the ground wire (yellow/green) and 62 volts between the orange and ground wires. This seems a little funky to me, so appreciate any input if anyone else has checked the voltage. I also put the solenoid back into Silvia, reconnected it and turned it on. Not magnetic with the brew switch on or off. There is no voltage at the solenoid when the unit is simply turned on or when the pump is sending water to the steam wand. I can compress the internal spring in the valve and it is clean. With the boiler disassembled and 3-way valve removed, air flows freely from the group head up into the boiler. With the 3-way valve in place on the boiler, air from the group head only flows out through the 3 way valve (normally closed position).
So, to sum up, I think I may have a low voltage issue going to the 3-way valve or something is not right with the spring in the 3-way valve. However, I am a bit stumped at this point. I appreciate any input - I am leaving tomorrow for a business trip and my wife is having coffee concerns.
SStones Senior Member Joined: 24 Nov 2012 Posts: 234 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 Fri Dec 7, 2012, 8:42pm Subject: Re: Rancilio Silvia 3-Way Valve Not Working
I don't know your machine well, but I think I am following what you're saying.
I checked the voltages across the three legs going to the solenoid when the brew switch is on. I have 27 volts between the white and orange wires, 110 volts between the white and the ground wire (yellow/green) and 62 volts between the orange and ground wires.
So your live wire is the white, and it is fine.. Your ground is fine too, as you're getting 110VAC from live to ground... but there's some huge resistance between your orange wire's connection at the solenoid and the neutral conductor at your plug. Follow the orange wire, if it goes to a safety thermal'breaker measure the resistance across that. If it goes to the "Brew Switch" measure the resistance across that. Some switch has built up carbon, is creating a lot of resistance and is about to burn out. So long as the machine is in good shape, you should have nearly zero resistance across the switch and any thermal breakers that might be in the neutral wire's path back to the plug, this means that with the brew switch on, you should read 110 VAC (Give or take a couple volts) across the solenoid valve's coil.
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