JavaJunkie-

When I descale - I run a dilute citric acid solution which I have added to the water tank - through the group head - but I do not use the boiler refill button to run it through the boiler.

I backflush wiggle all the time between shots - every shot, because, as you know, that grouphead sucks up grinds like a magnet. I run a detergent backflush through the grouphead about once a month.

I guess it is a somewhat fussy machine - you got to clean it a lot - and then there's that stat problem. However, despite it's faults I like it. The coffee quality, and the look.

Howard

howard seth wrote:JavaJunkie-

When I descale - I run a dilute citric acid solution which I have added to the water tank - through the group head - but I do not use the boiler refill button to run it through the boiler.

I backflush wiggle all the time between shots - every shot, because, as you know, that grouphead sucks up grinds like a magnet. I run a detergent backflush through the grouphead about once a month.

I guess it is a somewhat fussy machine - you got to clean it a lot - and then there's that stat problem. However, despite it's faults I like it. The coffee quality, and the look.

Howard

Thanks! Very interesting. I wonder if I've got some scale built up somewhere in the grouphead? Anyone have any idea if scale from the grouphead could make its way back down into the boiler and eventually into the pstat? Makes sense that anything that might be sucked into the boiler would eventually fall to the bottom thanks to gravity, and eventually be fed into the pstat. So, the big question is whether there can be anything sucked from the grouphead into the boiler! Maybe this is my problem!

Jack Denver posted on alt.coffee that the aluminum diaphragms on the smaller Pstats tend to get a layer of corrosion which exacerbates the sticky problem (a pressure stat's business end is an aluminum disk that bulges in one direction, then the other, like a clicker toy, as the pressure changes -- the sticky problem is that it freezes in the low pressure direction, and won't flip to the high pressure position). Jack poured citric solution into the end of the stat that connects to the boiler and solved the problem.

Jack's idea explains why the ones on the water side seem more prone to this. If this is the case, filling the boiler with distilled, may not be a good idea. Scale cannot be the problem. If corrosion on the diaphragm is the culprit, buffering the distilled with a bit of tap water, not enough to scale, but enough to raise the alkalinity, may actually improve matters.

BTW, I no longer feel that the Semi is a good 24/7 machine. Instead, it shoud be on an appliance timer and get a few hours cool off time each night. I don't know if this will help the stat; but I had pump problems from the small plastic ball valves inside the Ulka deforming and no longer sealing properly; and turning it off at night prevented that.

JavaJunkie-

Do you leave machine on all day? If not how many hours is the machine on?

h

harris wrote:JavaJunkie-

Do you leave machine on all day? If not how many hours is the machine on?

h

I have been leaving it on all day. Based on Jim's advice, I just put a timer on it, and set it to come on at 5am and go off at 9pm. That should cover me. I just want to be sure that at any time the mood strikes, I should be able to stroll up to the machine and pull a shot. That's why I bought a machine in the first place...

JavaJunkie wrote:I have been leaving it on all day. Based on Jim's advice, I just put a timer on it, and set it to come on at 5am and go off at 9pm. That should cover me. I just want to be sure that at any time the mood strikes, I should be able to stroll up to the machine and pull a shot. That's why I bought a machine in the first place...

That is one of the reasons I purchased the machine also, I wanted it on all day. After having a sticky stat in the first few weeks of ownership, I called 1st-line and was told the machine should not be left on. I protested using the HB and CG reviews as my defense but Jim (1st-Line) said to turn it off after use. So that is what I have done and have not had a problem since - about 8 weeks. They even sent (for a price) a new stat that I ended up not needing.

I can not begin to understand if being left on all day in hot water causes a sticky stat or not, I just know turning it off after use seems to work, for now.



h