Hi again, just bumping this back to the main page as I'm sure there are plenty of Linea users out there.
Is there a specific problem you are attempting to fix? What are you trying to achieve? Clearly you feel like there is too much water coming through your groups, but why do you think this? Providing more information would be useful.
I have done the install with a set of 6mm gicleurs to one of our two shop machines. I really like the effect, and have a set on order to for the other machine.
with the linea av the going theory is that the flowmeter is intended to be all the flow reduction it would need.
What I did to install them was to remove the tube and simply tap it with a machine screw I found with the same thread count and pitch. worked just fine. way cheaper than a tap. just remember to use lubricant, and only turn it in 1/4-1/2 of a turn before backing it off.
after the tube was threaded all that was left was to thread in the gicleurs, and disconect the flowmeters.
easy as that.
I did end up with one group flowing MUCH, MUCH slower than the other two, either I recieved the smaller gicleur, or I accidentally crimped it shut when I screwed it into the tube with a pair of needlenose pliers.
I LOVE the results in the espresso.
a) espresso extracts much more smoothly, little to no "glugging" or surging as the portafilter suck in air
b) espresso now "preinfuses" for around 7-8 seconds before beginning to flow
c) more body, better color, more complete extraction
1) requires longer flushes to acheive stable temp, and maintain clean screens
2) as a result ot the above requires more frequent backflushing (not a big deal)
I say go for it! I for one think the linea does well with a slower flow rate. the gicleur install at least halved the flow.
You can add pretty much whatever restrictor you want. on the Av lineas the Flowmeter was the original restrictor (about 1.2mm). Current production has added the 0.6mm restrictor. The flowmeter (made by Gicar) is designed fro a particular flow tare with the 1.2mm orifice. This design is to get perfect results. With the 0.6mm orifice you suffer about 5% error in the flow meter. Nothing that you will notice. The 0.6 mm orifice will slow the flow of water until the filter basket is full. Then the coffee is a bigger restrictor so after this is does not matter what orifice you have in there. In other words it only affect thi 1st 5-6 seconds of the shot (but it is a very important part).