I have a trane RTU unit serving half a building. The other half is leased out to other people. Well once it gets cool enough for econo mode I have serious pressure issues inside the other residents side of the building and the lobby. The walls are sealed up to the roof but im sure they are not air tight obviously. But my static pressure should not be building up enough to be forcing air into the neighbors space anyhow. I have replaced the static pressure transducer inside the unit and replaced the calibration solonoid and verified that it is zeroing out every minute. Ive adjusted my exhaust fan to be enabled once the economizer reaches at least 20%. The issue is that my exhaust fan still does not come on until the pressure inside the space is already to high. On the intelipack it says my pressure reaches around .5wc. I beleive it is still inaccurate due to the volume of air rushing out of the lobby door. I think my issue is the placement of the tubing for the static pressure transducers. There is a drop cieling in the space with return plenum but the drop ceiling is 18' in the air. The installers installed the tubing to stick 1" thru the drop ceiling into the space. My thought is that I am going to ensure that tubing is in good shape i.e. kinks, holes. and then Im giong to extend the tubing into the space closer to ground level. For some more added information about my issue the drop ceiling has egg crate returns in it along with some some missing ceiling tiles. Not many though. Once my power exhaust comes on my pressure in the space is solid. Its only when the econo initially opens and the exhaust fan delays coming on. Once on the exhaust releif dampers modulate according to pressure and operate perfect. Other then rerouting the tubing is there any other changes that I should be looking into to correct this issue. Im not very optimistic that this rerouting of the tubing is going to solve my problem. Any help is appreciated.