OK, so I did the dumb thing and almost lost Silvia this morning. Had her on a timer and somehow the brew switch got flipped on when timer was off. Woke up to my kids asking each other, "What's that sound?" Rushed out to the kitchen to find Silvia laboring, her reservoir empty and water all over the counter. It was an hour after the timer turn-on, so best guess is that Silvia's pump had been running for an hour. (Either that, or my 5-year old flipped the brew switch and Silvia had been running dry for only a few minutes, but I doubt it.)

Even though the pump still ran, Silvia wouldn't move any water when I refilled the reservoir. Shut her down, waited a few minutes, popped the cover and pushed the heater protection thermostat. Then Silvia came back to life with correct pressure and temperature. Pulled a few shots, steamed some milk, and all was well. Whew!

I was really lucky. Don't know why the pump survived. Maybe the PID pulsing saved the heater. Anyway, time for a thermal protection diode on the pump. But of course that won't protect the heater/boiler. I really don't want to leave Silvia on all night, so what can I do to protect her from a similar timer accident?

Seems to me the best solution would be a water level sensor mod. But I haven't been able to find any coherent details on doing such a mod. Can anyone point me in the right direction?

Now here's a crazy idea: If I leave a backflush disk in the portafilter overnight, serious damage to the heater might be averted. If the timer powers Silvia up with the brew switch on, the water will be flushed back into the reservoir. From there it'll circulate back to the boiler, to the group head, through the 3-way valve, and back to the reservoir. The reservoir won't empty out and the boiler won't run dry. The heater will remain immersed. The pump will keep running, so unless the thermal protection diode cuts in, it'll eventually burn out. But the pump is a lot cheaper and easier to replace than the boiler/heater combination.

Backflushing is the last thing I do each session (or it would be if Silvia was out of warranty, heh heh ), so it would be easy to just leave the disk in there. I have a rubber disk, but the stainless disk might be a better choice. The rubber disk might not completely seal, leading to a slow leak of water out of the machine.

Now, everything I've read says you shouldn't backflush for more than a few seconds, but seeing as how there's no detergent involved, what's the risk? Would a long run in backflush mode be any worse for the boiler seal than a short backflush? Would it be any worse to put this sort of strain on the machine than to let it run dry and blow both the pump and heater/boiler ($200 and probably a lot more work than replacing the boiler seal)? I would think the odds favor the thermal protection diode shutting off the pump, so it probably wouldn't run for hours. But at least the heater would be protected.

Does this make any sense in lieu of a water level sensor? I mean, it's not like it would be happening all the time. It's just a failsafe against a timer accident.

Oh yeah. One other idea occurs to me: run the heater AC through an on/off switch (a good mod to have anyway) and run a separate AC line from that switch to the timer. The main AC plug goes into a regular outlet, so Silvia stays powered up all the time and there's no chance of leaving one of the pump switches on by accident, but the heater (and only the heater) runs off the timer. More work than throwing a backflush disk into the PF, but perhaps a safer approach?

dgreen wrote:I really don't want to leave Silvia on all night, so what can I do to protect her from a similar timer accident?

It's not an issue that would worry me much, but a low-cost solution that comes to mind is replacing the stock on/off brew switch with a momentary switch (requires you to keep pressure on the switch to run the pump, similar to the one on the Rocky grinder), or timer switch similar to the one on Mazzer grinders. Either should be available at Radio Shack or Graingers.

dgreen wrote:How can I avoid a Rancilio Silvia timer accident?

The only times I've ever done this is when I wipe down the control panel with the Silvia off and accidentally hit the pump switch. Since the latest incident (years ago) I don't wipe it down unless its powered up and have not run into this as a result but YMMV.

dgreen wrote:Now here's a crazy idea: If I leave a backflush disk in the portafilter overnight, serious damage to the heater might be averted.

IIRC, it's not a good idea to leave the grouphead gasket compressed.

takeshi wrote:IIRC, it's not a good idea to leave the grouphead gasket compressed.

Excellent point. That eliminates the backflush disk idea.

I'm not the only person in the house, so I don't have total control over wiping down the machine. Putting the heater (only) on the timer or Dan's suggestion to replace the brew switch with a momentary switch make the most sense. Would probably replace the water switch with a momentary, too.

The steam switch is another story. Is there danger of damage to the heater if the steam switch is left on for a long time?

dgreen wrote:The steam switch is another story. Is there danger of damage to the heater if the steam switch is left on for a long time?

Yes. There is a significant risk of damage. Pressure inside the boiler at the top of the steam temperature cycle is usually high enough to force small amounts of steam through the imperfect seal on the OPV. Portions of the heating element that become exposed as the liquid level drops are subject to overheating and associated damage.

Jim

The momentary switch for brew and water sounds like a good idea. I bet after a few days using it, you'll be used to it and it will be commonplace.

As for safety from others and so other switches dont get hit, I have two thoughts.

first is to place a cardboard box over the machine when its off, like a cover. Not perfect, but its a thought.

MY other thought is, if using the momentary switch on the brew and water switch.. Then for the steam switch.. How about using a switch with one of those plastic covers over it. I think the Cimbali Max (not the Hybrid, the OG one) uses one of those switches. Might provide slightly more peace of mind over it accidently getting hit by someone else. A little label that says "Do Not touch" over the switch couldnt hurt either, though Idk how effective it would actually be.

dgreen wrote: Oh yeah. One other idea occurs to me: run the heater AC through an on/off switch (a good mod to have anyway) and run a separate AC line from that switch to the timer.

Put the timer on the lamp next to your bed. When the light goes on, go turn on Silvia, and go back to bed. If the pump is on, you'll (probably) notice it.

My method was to get up and turn on Silvia, go about my morning ablutions, feed the dogs, and by the time all that was done, Silvia was all warmed up.