Post By KJM
Post By brendogs
Post By KJM
Expobar Minore II - Steam Pressure Extreme!
I have a Minore II, which has been running fine for the past 4 years.
Yesterday it started hissing, I noticed that the steam pressure gauge was against the top stop. When I turned on the steam wand, the steam pressure was obviously much higher than usual, and there was water leaking from the unit.
The brew temperature was still sitting on 93oC, and the brew water flow was fine. Just the steam is the issue. .
I turned it off immediately, as obviously the temperature was way too high.
Where should I start checking to diagnose the issue? Is there a pressure sensor switch that controls steam pressure/temp?
What do you have the Steam Temperature Setpoint adjusted to mate?
Steam pressure is controlled by the pressurestat. They fail. It sits on a piece of copper pipe between the two boilers. The hissing will be the pressure relief valve. The water leak is most likely the steam condensing.
The brew boiler temperature will be mostly unaffected by failure of the steam side, but you basically have the steam boiler running continuously, and this is not a good thing...
Diagnosing the failed pressurestat ought to be easy - turn it on, when the pressure reaches the usual steam-off point - maybe 1.0 --> 1.4bar then the red neon should go out. If it doesn't and the pressure continues to climb, power down and you've got the problem nailed.
You can find quite good info on the google group for the US version of the Minore - called a Brewtus over there.
Thanks for the pointers. It seems to have only happened the one time.
Since then the steam sits between 1.0 and 1.4 bar, usually about 1.2. The red neon is now cycling as I would expect.
At leat now I know the baseline, as I had not had a reason to look hard at this for ages. There are no leaks now either
I will know better next time I see the problem,
I would highly recommend purchasing a replacement pressurestat and changing it over. A coffee boiler is under significantly high temperatures and pressures. A fairly dangerous combination in a family home. Although each machine has its own safety and preventative parts, negligently hoping "it'll come good" is not the mindset you should have.
Do yourself a favor and just spend the money and get the machine back to a safe and operational state. All it takes is to fail one more time while you're out of the house and we won't discuss what happens next.
What Brendon said The fact that the pressure is now correctly regulated implies (to me) that maybe there was some kind of obstruction to the pressurestat. They are basically a diaphragm with a switch on the other side. So if there is a blockage the diaphragm doesn't move and it is sad.. So there is probably something 'in the pipe' - scale maybe? Replacing the thing is simple enough (with no volts inside, of course...) Two spade connectors for the wiring (doesn't actually matter which way they go either..) and you unscrew the pressurestat and whack in the new one. You will need to seal the threads though - and this is where it gets expensive. You'll need to stump up for some Loctite 567 threadseal (or equivalent). Don't use tape.
If this was my machine, and this happened to me, I'd probably ensure the copper pipe is clear of obstruction and the boiler is descaled at the same time to prevent a recurrence.... but that's just me
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