About 1630, s5 TRH fan was being turned off. We upped the fan threshold current level from 80 to 150ma and now the fan is going (reading ~110ma). T and RH have been reading fine all the time, though who knows how good the signal is with no aspiration. We'll have to visit this site, with the idea of replacing this fan (and will have to reset the current threshold back at that time).