I have a deep drilled well not positive of well depth but the pump I know is sitting at 340 ft. we have been running out of water so we decided to add 50 ft to the original 300 ft. it worked great building to 50 psi consistently for 4 days the it stopped building pressure. We thought maybe it was bottomed out so we took it up again yesterday 7/30/11 took off 10 ft of pipe set the pitless on the edge of the casing and ran the pump for approx 10 minutes with constant water but we didn't pressure test at the pitless just assumed its pumping therefore its good. Dropped the pump back in and to ne evail we still cannot get over 30 psi in the house with the switch calling for water. My question is this the pump is 2 years old , but could it be a bad pump and can push the water as long as there is no pressure but when its hooked into the house there's pressure, preventing a worn pump from pushing what's needed?

Pump should last more than two years. Research pump make and model number for maximum depth and pressure.