Silvia

there are two class of expresso coffée: one produce crema and the other none. A 9 sec shot, means you are putting ground coffee that are way too coarse. The Silvia requires coffee grounf extremely fine, near powder texture.
Hope this help

Maybe you are (a) putting in too coarse a grind - try grinding it much finer (you really should have a Rancilio Rocky grinder), or (b) you are packing it too loose. Try putting more coffee in. I fill it level with the top of the holder, then take off a small amount with my finger to produce a kind of downward dished surface. Then tamp it fairly hard. You need a HEAVY tamper for this.

I recently cleaned my rancilio silvia by backflushing. However, I forgot to flush the system afterwards (the boiler was on) and I think the cleaning powder has baked somewhere and caused a blockage because no water comes through the group head. I can get water out the steam wand OK. Is there a product that will dissolve? Not sure just descaling will work because there isn't an end to end flow. Anybody got any suggestions how I can remedy short of taking the think apart? I

I get recently roasted coffee at the local coffee shop and have them grind it past espresso to turkish. It creates a much better creme. Also, make sure you tamp the coffee in the porta-filter. I think 30 lbs. is recommended.