I all way use white bead for NPD dedectors. When I change to Black bead. ( applyed replacement procedure)
Signal output unstable.
set to 30 pA. start adjust, 30min later complet adjust . But output goes to 15 pA and up to 30 pA. this cycle all ways continuous
h2 : 3 ml
air: 60 ml
h2 supplay pressure : 1.5 bar
air supply pressure: 3 bar
bead voltage off position : output 2.1pA.
I waiting your advice.