So I ran into a problem with my Diadema Perfetta this weekend. I turned the machine on in the morning and walked away to let it get up to temperature. After some time went by, I heard some loud banging type noises. I quickly realized it was the espresso machine and proceeded to turn it off. I let it cool, turned it back on and ran the water through the group. Nothing but steam came out. Eventually a small amount of water came out. Leaving the unit on reproduced the same knocking/banging noises.
Seems to me the temperature in the boiler got so high the thing wanted to blow. I've been having issues with the machine getting very hot after a couple of shots, but nothing that struck me as too odd. Something finally "snapped" as it's no longer usable.
Some back up...this is my only machine as is used daily. I descale it every three months and back flush it a little more frequently that that. I suspect the thermostat and did some digging around and found that on this machine, the brew stat is rated at 145 C and the hi-limit is rated at 200 C. These seem awfully high when compared to replacement stats available online, so I'm not sure what to make of this.
If anyone has any suggestions on things to do to rule out certain components, your help is greatly appreciated. I would also love to take this to a certified tech, but I'm relatively new to the Houston, TX area and don't know any reputable places around here. Feedback on that would also be appreciated.

I believe that this is a single-boiler, dual use machine (no HX). I have to guess as little info was found about the machine, but if it is controlled by thermostats then the brew thermostat is stuck closed or the steam switch is stuck closed. If it has a pressurestat then the pressurestat's contacts are stuck in the closed position.

Correct, it is a single boiler, dual use machine. My understanding is that this is a re-badged BFC unit. Viewing the PDF at the link below will show you what's going on inside my Perfetta.
http://www.risteriet.dk/catalog/pub/bfc%20perfetta.pdf

OK... that helps...
1 - Does the hot water function work? When you first turn the machine can pump a normal flow of water through the wand?
YES: that would indicate that the pump is working and sending water to the boiler. Go to 2
NO: there is a problem with water supply, the pump, and/or related piping

2 - There is a problem with the brew thermostat. The brew thermostat is closed (internally welded contacts) and so even though the steam switch is off, the machine is in eternal steaming mode. Check the brew thermostat with an ohm meter or continuity tester and replace as necessary.

CAUTION: it might be a good idea to disconnect the machine from the wall outlet and disconnect and insulate one of the wires leading to the heating element. Then plug machine back in to continue testing. Since water seems to not be getting into the boiler you risk damaging the heating element and other components from overheating!

Randy, thanks for the feedback.
When I first turn the unit on, I can get water to come out of the wand and can hear the boiler filling up. Only if I leave it on for say, 15 minutes, does the boiler start to knock as all the water has turned to steam.
I'll check the thermostat when I get home and hopefully identify it as the culprit. I've gone 3 days without home brewed espresso and I'm not sure how much longer I can keep that up!

Should be a simple test. I would remove the thermostat from the machine and clamp the test leads from an ohm meter on the contact tabs. Should read near zero ohms (full continuity). Heat the thermostat with a heat gun and when it hits about 190-205 or so it should open.. The temperature is a guess because the ratings they give are odd - they call the two main thermostats 165C and 200C which is crazy if that is centigrade... I mean, 329 and 392 F!?! Can't be.

Time for a PID....?

well it was the thermostat. just got a replacement and the machine is back on line. thanks for the help Randy.

rivera618 wrote:thanks for the help Randy.