Post By Dimal
Rancilio Silvia - Excessive Steam From Grouphead
I'm hoping for some technical help as I've explored every option I can think of. It's a one owner V2 model I've had since new. These are a simple machine and I'm quite technically minded and have done all repairs, parts replacement and servicing myself over the 10 years I've owned her and it's never missed a beat....but this recent issue has me scratching my head.
It's developed excessive steam build up from the group head when purging before a shot....to the point where I can run half a tank of water through the group and it's still steaming and produces that typical 'whoosh' when switching off that would suggest excessive pressure and build up. Pulling a shot usually results in a scalded puck and an excessive steam surge when the brew button is switched off. This is not the normal amount of steam or pressure when purging....it's excessive and won't stop.
These are all the things I've done (and/or parts recently replaced).
1. I recently installed a new OPV (which now functions properly as excessive water no longer runs back into the water tank) and it's been set to the correct 9 bar pressure (using a gauge). I've even lowered the pressure to run a check but this made no difference.
2. I've dismantled and cleaned the 3 way valve and it flows through perfectly.
3. I've measured the brew and steam thermostats using the Ohm (or continuity) test with a multimeter which showed around zero ohms or full continuity, which indicates they're working properly.
4. I recently replaced the shower screen and group head seal and cleaned everything in backflush solution.
5. The unit has been descaled and has been regularly backflushed since new.
As I said, they're a simple machine and I think I've checked, dismantled and cleaned everything I can think of (as well as the usual cleaning it receives anyway).
Any technical advice on what it may be would be very much appreciated....or if you've experienced this in your own machine and can offer some insight. This is more than a case of installing a PID (which will improve an already well functioning machine)....this is a case of a problem that has developed which I would like to diagnose.
In light of all of the above I would love to hear your thoughts.
Sounds like either a thermostat or whatever is switching the element has stuck closed. Does the heating light ever turn off?
Yes, the light turns off. As mentioned in the post, I've put a multimeter on the thermostats.
If you're comfortable that you can be safe with 240v, I'd try measuring the voltage at the heating element when the light is on and again when is off to see if the element is actually turning off.
Given how inexpensive new t/stats are, why not buy replacements for your machine and be done with it...
Good idea to replace all at the same time.
Yeah, replacing thermostats is easy and cheap enough....I guess it's the last thing to do. Thanks
It'd be the first thing I would do...