Rancilio Silvia Boiler Issue

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

#1: Post by despower »

Hello Forum,

I have a Silvia with a pre-2006 boiler. The boiler has been replaced once and the unit was working fine up until a few weeks ago. I noticed that the Silvia was not heating up, so I popped the lid and saw that the 165C safety thermostat had popped so I pressed the button and presto - the unit started heating up again. Except it overheated again and popped the thermo (and made lot of interesting noise BEFORE it did that). Without doing much troubleshooting, I decided that the 100C thermostat was blown, so I ordered replacements to both the 100C and 140C thermostats. I installed these today.

The result was that the unit started heating up again (as expected) - I checked the voltage across the heater just to be sure and it was getting 120V (as expected). However, the light on the main switch does not go off - indicating to me that the machine may not be heating up to 100C. I continuously watch the volts across the element and sure enough, the element is getting power without tripping. I ran a brew through, and the coffee comes out hot - at around 80C. I do not have a temperature probe to check the temp of the boiler to see if it gets up to 100C. I decided to leave the machine on to see if the light would eventually go out - it did not. However, after about 10 minutes or so, steam starts coming back through the return tube into the water reservoir. At no point does the 165C safety shut off engage, although obviously it did the first time it happened before I changed the 100C and 140C thermostats. So, it seems that the heater is heating up the water, but the thermostat isn't turning the unit off.

So, for me next step, I feel as if I want to change the boiler element, which for me means an entire boiler retrofit because my Silvia is a pre-2006. This is a large purchase, so I wonder if anyone has any thoughts about what I should check next? I was going to check the resistance on the boiler element, but my ohmmeter is giving me trouble. I'll report back when I get a better ohmmeter. If anyone has any thoughts on what to check in the interim, I would be happy for the advice.

Best Regards...

Des

Nunas
Supporter ♡

#2: Post by Nunas »

When you get your VOM working, check here http://www.espressomyespresso.com/Silvi ... iring.html As you can see, the brew and steam thermostats are on the ground side of the heater. The safety thermostat is on the hot side. Using your ohmmeter, check the heater pins to the frame (ground) for a low reading or a short (should be open...no resistance). If the heater shorts to the ground anywhere other than the hot side pin, then the other two thermostats are effectively bypassed and the crippled heater will continue to heat as best it can. Left on, the machine will heat indefinitely until the over-temp thermostat pops, or the heater fails open (which it may or may not necessarily do).

despower

#3: Post by despower »

Thanks Nunas... I'll check that.

A small update. I turned the steam switch on, which effectively engages the 140C thermostat. The machine did not heat up enough to steam the milk and I waited a long time, so i believe that I now have a faulty heating element - possibly thanks to the previous overheating.

I'll have a better ohmmeter tomorrow and I'll post some numbers.

Des

despower

#4: Post by despower »

I decided that I would take my boiler apart. This is what I found inside - yes, we have really soft water where we live. Seems like the element has exploded. The photo only shows one crack, but it's cracked in a whole bunch of spots that you can't see in the photo. At the bottom of the boiler was a pile of crud, which I am guessing are the insides of the element. Surprising that it was able to heat up at all.

I think I need a new boiler - what do y'all tink?




Nunas
Supporter ♡

#5: Post by Nunas »

I don't know about a whole boiler, but you certainly need a new heater! The crud in the bottom is likely just that...crud. I'd take the heater out of the boiler clean the boiler up at least somewhat before going to the expense of a new boiler. Of course, due to the different heater configurations over the years, it may just be that a heater/boiler is your only viable option.

despower

#6: Post by despower »

That crud is actually the insides of the heater element. Pretty catastrophic failure of the element - but Iv'e seen similar in home hot water heaters. My unit is a pre-2006 Silvia so the boiler and heater element are one unit. So, I had to replace the boiler with an upgraded version c/w replaceable heater.

despower

#7: Post by despower »

Got my new boiler today... the old boiler is basically open circuit - 7.29 Mohms. New unit is 15.8 ohms (I have a 120V unit).



despower

#8: Post by despower »

Here's the new boiler screwed in place. And a photo of the reassembled Silvia in place for tomorrow's breakfast.