I have an old dug well with a 1" poly suction pipe in the basement. The well is about 60' away from the house. I'd like to setup a sprinkler pump, but the 1 1/2 hp pump I have has a 1 1/2 inlet and it's only building about 20 psi of pressure with outlets closed. I'm assuming the 1" suction pipe is the problem. Could something else be causing this? Thanks.