I would agree, the original IH low-pressure (400psi) rubber hose is VERY important. Part n should be 688190C1. I find it hard to believe they discontinued that, I haven't gotten any in the last 6 months, but it was never a problem and always a stocked item. Yes, if your's is a later 1440 with the little ticker pump above the water separator filter, make sure its ticking as they seem to go bad somewhat often. Also take tank cap off and bottom tank line loose, and take air hose and blow backward to be sure that the tank outlet isn't plugged. Good luck!