Water pressure - exits portafilter too quikly

It is possible that the grind you are using is too fine and causing so much back pressure that the portafilter is moving, also possible that the group gasket installed need to be replaced, I have also seen this happen with damaged screens.

It should not leak steam out of the grouphead. The three way valve is leaking.

First of all if it is new, get it fixed under warranty. The three way valve is a replaceable item.

On the other hand if you are like me, you can try a back flush with just a tiny bit of coffee machine detergent like "Joe-Glo". The directions might say not to do this but if it is my machine, it's my machine

1. Get a rubber disk for back flushing. Any place that sells the detergent should sell the disk.
2. Put the disk in the portafilter and add just a few grains of detergent.
3. Install the portafilter and "brew" for about 20 seconds, then switch of for 15 seconds or so..
4. Refill the water reservoir as needed.
5. Repeat the "brew" cycle until you get "detergent water" in the catch pan. It may take 6 to 8 cycles.
6. Remove the back flush disk from the portafilter, reinstall, and run a couple of normal 30 second brew cycles to flush detergent out the valve and grouphead.

If this was a coffee maker in service for a while and might have a water scale buildup, I would do the same thing but I would dissolve some citric acid in the water reservoir and descale the boiler, valve, and grouphead at the same time.

Try to redo what you have been doing, but set it to the extremes to see if everything is functioning. If you set the grind say to 4, it should come out very slow or maybe not at all.

Have you ever changed the brwe head gasket? It should be changed yearly at least. They get hard from the heat and won't seal. They should be soft to make a good seal. You can change it your self. I have left post on changing gaskets. Look for Silvia solutions.

Correct
When you are finished and turn the pump off, the 3 way valve opens and relieves the pressure in the brew head so you don't get an explosion of coffee when you remove the portafilter.

Check the shower screen, make sure it is not clogged with coffee oils and back wash the head.

Hi
The solenoid valve needs back flushing the correct way with a espresso machine detergent like Cafiza, or Joe Glo. Place a 1/2 teaspoon in a blind basket. (don't come with Silvia). Place blind basket in portafilter and brew like making espresso, but run pump for no more than 5 to 10 seconds or until the pump starts to change tone (slow down). Stop the pump when either of these things happen or Silvia can be damaged. Repeat the pump 5 to 10 times leaving a 1 minute wait between cycles, or the suds comming out the 3 way valve turns pure white, with no coffee stains in the foam. Remove the portafilter and rinse then reinsert and repeat the cycles to rinse the internals. This should take care of the problem. If not you may have to replace the 3 way.

try adjust grinder,try go litlle bit courser ,check screen it need to be clean.

Try running the gro;up without the portafilter in place, what does the water flowq look like: is it a nice strong flow or barely a dribble. If if is barely a dribble, backwash machine with purocaff and check shower screen, that may be clogged. If you have a nice flow then try adjusting the grind on the coffee grinder.

from your description i can conclude only 2 things:

1. coffe grinded too fine
2. pump pressure low

i think you can chek these 2 and have your perfect espresso again