Rancilio Silvia pump not working

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
noaham

#1: Post by noaham »

I bought a used Silvia recently. It was in good condition and working find, but quite dirty. I just finished giving it a deep clean and put it back together. The first time turning it on, the pump took in some water (maybe a quarter of the tank) but then stopped. The flow through the machine slowed to a trickle. Now when the brew or water switches are turned on the pump quietly vibrates but does not take in any water and there is no flow through the machine at all. I have tried priming the intake hose but no luck. I have already disconnected the leads to the heating element.

Any leads on what might be the problem are appreciated!

JRising

#2: Post by JRising »

My guess is the pump's dead. Very easy to replace.
If the pump is so weak that you can stop the flow out of the steam wand with your thumb (Or it doesn't flow at all), then the pump's too weak and should be replaced.

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THZ

#3: Post by THZ »

Yes - quite easy, see https://aerotec73.wordpress.com/

noaham (original poster)

#4: Post by noaham (original poster) »

Thanks for the replies and the info. Definitely seems like the pump is dead. Is this something I could have caused while cleaning the insides of the machine? It was working fine before.

After posting I also noticed that when I turn the pump on, it gets quite hot, to the point that it is too hot to touch. Is that a further sign that it is dead?

kray

#5: Post by kray »

Check the wires running to it and the contact points. If the pump itself it hot to touch. You've got it.

noaham (original poster)

#6: Post by noaham (original poster) »

Very strange thing, I woke up this morning and the pump is working fine. The only thing I can think was happening was that there was air trapped in the pump? But the pump wasn't pulling anything in the intake hose through. Anyway, all good now

noaham (original poster)

#7: Post by noaham (original poster) »

I spoke too soon. It was working this morning and now as soon as I put it back together it stopped working. I turned it on and the pump was operating normally and water was flowing through the group head normally. Then I switched to hot water and the pump immediately slowed down and the flow through the steam wand was extremely slow. Switching back to brew did not return the pump to normal.

Is this still consistent with a pump that needs to be replaced?

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JRising

#8: Post by JRising »

Try: Brew Switch Off, Middle Switch (Water) on, Steam Valve Open... Try to stop the flow from the steam wand with your thumb over the end. This is less burny if you do it before the machine has a chance to heat up. If the pump isn't strong enough to pump past your thumb trying to stop the flow, then the pump is useless.

noaham (original poster)

#9: Post by noaham (original poster) »

I can reliably reproduce the issue now! The following steps cause the pump to only pump very weakly when with either the brew switch or water switch on:

1. Turn on brew switch. Machine pumps normally and flow is normal.
2. Turn off brew switch.
3. Turn on water switch. Machine pumps normally and flow is normal for about 5-10 seconds. Pump suddenly becomes much quieter and flow becomes weak.
4. Regardless of whether brew or water switch is turned on, the pump and flow is weak.
5. If I leave the machine off for a little while, the operation becomes normal, but I can use the above steps to reproduce the issue.

Regarding placing my finger over the steam wand: predictably my finger will not stop the flow when the machine is operating normally, but will stop the flow when the pump is weak. Don't worry, I'm doing all this with the heating element disconnected!