La Pavoni Europiccola - thermofuse trips often

A haven dedicated to manual espresso machine aficionados.
martinlhoff

#1: Post by martinlhoff »

A few months old EPC-8, generally working like a charm, ~5 daily shots to keep me productive through the workday.

So far only 'work' has been tightening the 'neck' screws and the steam knob to handle leaks. But now I have a new misbehavior. Left on for a few hours, there's a 50:50 chance it'll trip the thermofuse. Epitome of first world problems: mid-morning I walk to my Europiccola and it's cold and not ready to make me a coffee.

This started ~5 weeks ago. First few times, it seemed that the pressurestat was stuck, or the release valve spring weak, because it tried to boil itself dry, spurting water over the release valve. I'd hear the noise and come sort it out. But that hasn't happened in the last 3 weeks - no release valve issues (it still works well if I overfill slightly, so it's not jammed shut). Just that on any given day, I switch it on at 7am and by 2pm there's a 50:50 chance that the thermofuse has tripped "silently" as far as I can tell - or at least without causing a rucus.

Thoughts on what it could be?

baldheadracing
Team HB

#2: Post by baldheadracing »

Assuming that the thermofuse is tripping because there is no more water in the boiler:

The tip of the pressure relief valve includes a very small vacuum breaker. The breaker can get stuck and not fully close. (It seems more common for the breaker to get stuck closed and never open, but that's not your issue.)

If you have any scale potential in your water, then the breaker assembly will need to be removed for fairly frequent cleaning.
Good luck!
-"Good quality brings happiness as you use it" - Nobuho Miya, Kamasada

martinlhoff (original poster)

#3: Post by martinlhoff (original poster) »

I use filtered water, but there's still some limescale in it, I'm sure.

But to be clear, it's _not_ boiling itself dry. It typically has more than half the water tank; when it trips I find the machine cold, but still with at least half a tank of water. When it trips, the water level doesn't change significantly from where I had left it.

baldheadracing
Team HB

#4: Post by baldheadracing »

Ah.

The thermostat is rated at 127C. https://www.espressocare.com/products/i ... ostat-127c The machine could exceed that temperature if the safety valve was sticky. If it were my machine I would disassemble and clean the valve (and vacuum breaker) and see if that helped. However, that does require some specialized tools (thin wrenches), and it would be desirable to have a pressure gauge to confirm boiler pressure and valve operation. I'd also inspect the wiring for any issues like charred connectors.

Regardless, a machine a few months old is still under warranty. That might be your best option.
-"Good quality brings happiness as you use it" - Nobuho Miya, Kamasada

martinlhoff (original poster)

#5: Post by martinlhoff (original poster) »

Good point. I did tap it once or twice.

Short of complicated disassembly, is there a way y to jiggle it free, them rinse it clean?

baldheadracing
Team HB

#6: Post by baldheadracing »

Have a look at this video from Stefano, but ignore the part with the second special wrench that goes inside the boiler. You do need what he refers to as a "skinny" open-ended wrench.
-"Good quality brings happiness as you use it" - Nobuho Miya, Kamasada

Blernsball

#7: Post by Blernsball »

If I had to guess, it's probably because you are leaving the machine on all day and the heat is eventually building up enough to trip the fuse.

It's not a commercial machine designed to run all day. Fire it up, pull a shot, shut it down.

martinlhoff (original poster)

#8: Post by martinlhoff (original poster) »

Armed with knowledge from this discussion, over the next few days I filled the tank to the very top every time. I worked the lever in short pushes to relieve the false pressure buildup.

Overall, the pressure/overflow valve got some exercise.

The problem hasn't reoccurred.

:D

martinlhoff (original poster)

#9: Post by martinlhoff (original poster) »

Blernsball wrote:If I had to guess, it's probably because you are leaving the machine on all day and the heat is eventually building up enough to trip the fuse.

It's not a commercial machine designed to run all day. Fire it up, pull a shot, shut it down.
I work all day, and I like a quick punchy espresso between meetings. A half hour espresso routine wouldn't work for me. I think the machine can handle this alright.

Blernsball

#10: Post by Blernsball » replying to martinlhoff »

You do you. But the machine isn't designed for that kind of use and that IS why it's overheating and tripping the fuse. You are relying on the pressure relief valve to keep your element from cooking itself (which as you have experienced, is not the most reliable of devices). In general, the thermal protection in the europiccola is pretty rudimentary and doesn't do well when the water level drops in the boiler. The element can easily fracture before the thermal fuse is tripped.