Why is any water hardly comming out?

needs cleaning? Have the filters been replaced recently? Is there a leak in the system?

did you purge the system after installation? and do you have a storage tank with the model you purchased?

After it is first installed and every time you change the membrane filter (the middle one) you need to turn it on and let it run over night to remove all the air from the membrane filter. Then shut it off and let it make it's water / fill the tank. Then you will have a nice supply of water. You must let it run to get all the air out. I own this R.O. System and it works great.

Either a couple reasons. One is if a new install, it will take quite a number of hours to fill the tank as it takes some time for the water to get through the filters/membrane. Once you have the tank full, then the pressure should be fairly good. The other is if you've had it for some time and the filters are plugged, and even really hard water, then this can cause it to slow down the water filtration production.