Anyone had an intermittent heating problem with a Silvia?

Went up after lunch and it was cool to the touch. Ran the pump for 7-8 seconds, boiler didn't come on. Turn on steam switch boiler comes on, and confirmed it's heating by sound.
Opened it up and checked across thermostats (after following appropriate safety precautions of course), they're both shorted. Discounted the high limit as the steam switch fired up the boiler.
Put it back together, it works for a while. then quits. I'm monitoring voltage across T1 (110 degc thermostat) right now. It's definitely open when it won't heat, 119.5 VAC across the contacts.

Looks like an intermittent 110C thermostat. Anyone ever seen a soft failure on a thermostat?

At least it's a cheap fix. I'm upgrading in April to something nice (HX or DB), so was dreading having to drop any significant money on repairing Silvia.

Well, it's run for a couple hours without failing. Just made an espresso. As long as it can limp to the finish line.

Hi Eric,

I've had that problem 2 times, and both times it was the same issue: the extremely hard water we use from the well here had clogged up things. The problem begins intermittently, but then progresses to no heat altogether.

I was incorrectly told by a manufacturer that filtering my water with his product removed the hard minerals, so I didn't figure it out for awhile and thought I'd not changed my filter enough. Fortunately, a local electronic company around here does a thorough clean out. I now have that little water softener you can get for a Rancilio http://www.1st-line.com/parts/rancilio/homewatersoftener.htm, plus I descale and back flush religiously. So far, no repeat of the problem.

Les - thanks for the tip. I have very soft water so scale buildup has never been an issue.
Two days and no more failures. I'm sure it's only a matter of time till the thermostat goes hard, but for now it fine.