MicroCimbali Lever - Page 2

[Makanmata]

Afraid that my quest for citric acid today went unfulfilled. It was stocked at 0 of 6 local pharmacies, although one said that they could order it.

I was though able to find Urnex Cleancaf, which is a product aimed at home drip coffee machines. As it was the best I could to for today, I bought some and mixed it to double regular strength. It has been soaking for several hours now, and so far little joy. While I do think that I am softening some of the scale, I haven't been able to budge the valve on the hot water tap. Without being able to close that tap, I don't think that I'll be able to get the boiler under proper pressure, even if I can get scale free.

I just don't know what is going on with that water tap valve. Maybe some more soaking will do it. It would be nice to actually be able to make a cup of coffee on this machine sometime soon.

[orphanespresso]

What part of the water valve wont turn? Is it the knob (and stem)? Or, is it the nut that holds the valve together?

I don't think it's wishful thinking - I think you are right - there is a bit of scale stuck in the valve that isn't allowing the valve to close completely, thus the drip. You could take the valve out by loosening the collar, then turning the valve handle CCW (counter clock wise) till the whole thing comes out. You should see some o-rings, and the end of the valve shaft is pointed. That is where it seals against the valve seat. Bits could be anywhere along the shaft/seat, o-rings could be shot as well (all leading to leaks, but all fixable).

[Makanmata]

It is the entire stem that is completely frozen and locked into position. I actually removed the locking nut, as well as the handle (black wheel), but that stem just won't budge. Initially it took little effort to turn the valve, and in fact the wheel is only attached by friction (and therefore designed to turn easily). Its been soaking in double strength cleancaf all day now, but with zero difference to the tap (although I have managed to get more scale out of the boiler).

I will take you advice to try to open it up, although it isn't at all clear to me looking at the valve how it screws out of the boiler.

Thanks again for all of the helpful advice.

[mogogear]

Have you checked into Beer making or wine making supply stores? That is the best place to find this stuff in my neck of the woods?

Also On Ebay I found Citric acid 2oz delivered - less than $3! Check it out................................

[TUS172]

Stray voltage may also be due to a bad heating element leaking voltage into the water. Don't know how easy it is to find replacements. PC

I can atest to that as a fact. I had a pavoni that I had just gotten and it was blowing the GFI in out kitchen outlets. But if I hooked it up to a 20A circuit it was fine... That is until I was reaching across the top of the unit once and happened to brush the steam tap... Bang I get the jolt of a lifetime.

When I tore the unit apart the heating element shield had melted away in the second coil down from the top... totally exposing the electrical to the water. I should have known better when it was blowing the GFI circuit in the kitchen.

[orphanespresso]

This is a pic of the valve from our machine - we loosened the nut, and turned the valve out of the machine - there may be scale in the threads of the shaft making it difficult for you to turn it (try turning it in, then out to break it free from the stuff - I wouldn't use too much force, but you might need a little...)

Funny about the citric acid - we just got a 50 pound bag yesterday.

[Makanmata]

Unfortunately, my stem is absolutely stuck in its present position. When I forced the wheel, it lost its "grip" on the stem and began to spin freely. My wheel is now off, and the nut removed as well, but that stem is still lodged in the valve assembly and just won't budge.

I'm wondering if I should order and wait for the citric acid before trying to pry the stem free with a wrench (although it seems like it would be very tough for a wrench to get a good grip.

[orphanespresso]

Not sure what to tell you - but, this is what I would do (and, we have a bit experience, and a bit of derring do so risk isn't scary). From your description it really seems as though there is debris caught in the threads on valve stem. I would put the screw on the end of the shaft to protect the threads and tap on it with a hammer (to attempt to pulverize the scale debris - much like lithotrypsy on a kidney stone, but with a hammer instead of a sonic blast), then jiggle it, tap & jiggle, until the stem is loosened. If the valve opened & closed fine before, then something new has gotten in there. Since you have been descaling, loosening the scale bits, it stands to reason that the scale bits have become lodged in the threads. Once the scale bits are reduced to a small enough mass, the screw (valve stem) will turn again. Turning it with a wrench isn't a bad idea, but it seems that only a pair of vise grips would do, and that may chew up the shaft (you have to decide if the jaw marks are worth the risk versus a stuck valve)

[Makanmata]

Lo and behold, I found Citric Acid this morning shopping in a gourmet food store, so will not have to wait for a delivery.

I will follow the above lithotrypsy procedures to try and remove my "stones," but will give it another good soak with the acid first to see if that might speed things along and smoothen the procedure.

Thanks again.

[Makanmata]

Just a progress report. Roughly two hours into the soak (50g Citric Acid+1l water, cycling the heat on and off), the crust is practically disappearing before my eyes. I've got a long way to go, but I have no doubt that this will deal with the scale.

The problem is that so far, I still can't budge the valve stem, despite lots of jiggling, knocking, tapping, and some banging. It was tough to get a good grip even with the vise grip, but I think I got enough torque on it that I would be able to move it if it was possible (I am also concerned with mangling the stem). Another source for pessimism is that although the acid is slowly dripping out of the tap, it is not bringing with it any debris at all, indicating that whatever is in there (if anything) is not burning up too quickly at all. In any case, I am giving the acid another several hours at least to see what happens.

[mogogear]

Hopefully that acid-laden steam will also help free up you valve stem,, don't force it too much- patience will win the day yet! So just keep letting it cycle- leave that stuff in over night- then dump and add some fresh and do it all again.

You will be there soon - relatively At least you have the right concentration of acid on your side to really effect the scale build up. Most likely the steam valve just has the crusties too!

[Makanmata]

I went ahead and let the acid cook most of the day yesterday, with generally impressive results. My sight glass is now clean as a whistle, and while there are still some small calcium deposits here and there, the tide of the battle has clearly been turned. Aside from ridding the machine of nearly all of its scale, the stray voltage situation has entirely abated, proving that it was a scale related condition.

The bad news is that despite all of the progress, there is still no joy on the water tap front (not the steam valve, which is fine). The tap valve is still entirely stuck, and still slowly dribbling at more or less the same pace. At this point, I'll declare the battle against scale a draw, but I will be back next weekend with a fresh supply of citric acid.

[mhoy]

Any updates on the battle?

Mark

[popeye]

I also have a microcimbali. The boiler is aluminum, so it's my understanding that any type of chemical descale can be pretty harmful. I picked mine up this past winter and did a scrub & scrape descale. I then mounted a thermocouple externally between the brass "grouphead" (really the portafilter lock-ring) and the boiler/piston assembly. PID'd, it's an amazingly stable machine because the group is fully immersed in the boiler. I used it a few days but then set it aside because the boiler was corroding before my eyes. I have a commercial water softener (ion exchange) and my water tests as completely soft, yet some type of buildup/corrosion was going on and even continued after I emptied the boiler of water. It's been sitting for a couple of months and looks like i'm trying to grow sugar crystals in it right now. Anybody have any ideas what's going on?
Long term project - i hope to order a stainless steel cylinder the same size as the piston design and replace the aluminum boiler with my stainless steel cylinder. I could bolt the brass grouphead on the bottom, and wrap PID'd heater blankets around the outside for heat. I could even leave the top open for easy refill. It would be an awesome one shot machine that would probably be stable to within 1 degree.

[matthyx]

Wow, this sounds like an interesting project