Water Pressure to fill Hotwater tank in the Loft

Hello,
I have installed a new water system in my cottage and I don't seem to have enough water pressure to fill my hot water tank.
I'm using a submersible pump to fill a pressure tank under the cottage (150 feet from the lake with a 60 feet vertical drop). The pump and the Pressure switch seem to be working, when the pressure in the tank is below 30 PSI the pump starts and stoping at 50 PSI (it takes just 2 or 3 seconds) Water comes with a lot of pressure imidiately after the tank (garden hose) but in the kitchen sink (6 feet above) pressure is much lower.
My 28 gallon hot water tank is in the loft (14 feet above the pressure tank) and it starts filling up but after a wile it stops and i can't get any water comming out of the hot water pipes.
Do I need to increase the pressure of the swich? is my hot water tank to big or to high up?
Thanks for the help!

Without knowing the maximum head pressure of the pump I can't accurately diagnose the system. That said you might turn the long screw on the pressure switch clockwise to increase the pressure. Each complete turn will increase the cut-out pressure 1-1/2 lbs (Don't tamper with the short screw). Check to be sure the pump can still build up pressure and cut-off by running the water until the pump comes on, then turn the water off again to see if it will build up and cut-off. You could probably set the cut-off pressure to 70 psi and be ok. This should give you sufficient pressure everywhere. If you set the cut-off pressure to 70 lbs you should reset the air in the tank bladder to 48 lbs when the pump is turned off and all pressure is off the system.

Air Pressure

Problem solved, turns out the pressure tank did not have the correct air pressure, I set it up at 28 PSI and now I have enough pressure to fill the hot water tank in the atic and comes nicely out of my taps.
thanks for your help!