Clarus 500 AIR flow disconnection

We are having on Clarus 500 AIR flow disconnection problem for set flow of Air:H2( 450:50),We checked possible leaks loaction but couldent identifed .Atempted by swtiching off the GC 1-2 times and onec it on AIR:H2 flow is showing ok but later on AIR is getting droped from thye set floow rather its observed to be of uncertain fluctuation.How can i overcome this problrm.

please Guide