I have a pressure gauge remotely mounted with 15′ of capillary and a diaphragm seal. The seal is installed 10′ above the gauge. I am seeing positive pressure on the instrument with zero pressure on the pipe. Is this normal?

Yes. What you are seeing is the head effect from the weight of the fill media in the system. The assembly is calibrated with the seal and instrument at the same level at the factory. Once installed, you can re-zero the instrument with no pressure on the system.