I have a new (used) Vivaldi i have just plumbed in - everything works, except.... well brewing espresso.
After a lot of trial and error i have concluded that there is flow/pressure problem in the group.

(please note - this is a bit special machine. It is a Vivaldi II but in a Vivaldi I housing, apparently only sold in Italy - so only boiler pressure manometer).

It shows when you brew, at first i thought it was due to my inexperience with 53mm, I went from 2-3 on my K30 WBC to around 7 (both my Izzo Duetto and Quickmill was around 2-3 on the grinder for the "perfect shot"). No luck. (i have disabled preinfusion in my testing efforts).

- When i try to turn on the pump without a portafilter there comes an normal flow the first 1-2 seconds but after it almost stops to a drip.
- I get around 80g water in 1 minute without a portafilter.
- When brewing there is no drops for 20sec and then suddenly i get 40g in 30 seconds.
- No or very little crema (fresh roasted coffee i have very good experience with)

I have tried a lot:
1. Problem with my plumbing? No - when i disconnect at the machine and open i can fill 1 liter in a couple of seconds.
2. When i empty 800g water from the steam boiler, it fills in about 40-50 seconds without any problems.

A couple of videos:
http://www.youtube.com/watch?v=63hVqvrg4y0
http://www.youtube.com/watch?v=o6zlMedHq5I
http://www.youtube.com/watch?v=CbmFxm-ZEMs
http://www.youtube.com/watch?v=eEA36WO8VmE


So what can be my problem? What would you recommend? I can see a valve, expansion valve, 3way-valve and flowmeter from the pump to the grouphead.

Try the spaziale forum, you can generally find an answer there to these types of questions

s1cafe is definitely a good place to get help. Your shots are bad because of whatever is causing the water flow problem, so there's no point in trying to pull anything until you get that fixed.

For those who are interested, the OP continues the discussion here: http://s1cafe.com/viewtopic.php?f=57&t=2202