First call of the day worked on Lennox 10 ton rtu found evap iced up, let fan run pulled y1 comp 1 still ran thought that was strange pull coil wire turned unit on had low back normal head looked for restrictions on liquid line non took superheat of Evap and.comp found low went down stairs diffusers.found 2 flex closed opend them up suction.line temp came up back pressure came up think I got what.was causing it up