new to oil couple questions

heatmizer

First  on a Carlin burner  s/s  i am assumeing  service man switch  because looks like in series  before the primary  ? second not really oil guestion  but if im adding  a unit heater  to  one pipe  system  and one venturi/monoflow tees  and cannot get the propper pressure differential from one tee  do i just flip the tee on the return side or do i need a special tee  for this?

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heatmizer from my mentor..

my mentor used to tell all our rookies, coming back from nify to forget what they learned,and be ready for his training,in the real world.looks like you want to run before you learn how to walk.good luck.

heatmizer

lol

lolok i agree100%   but im in school  have 14 years  as  hvac tech  taking oil/steam class  now  and these  are just guestion i came up with reading  not really jumping in deep end  just in my head,   i do know the mono flow gose on return  just typed wrong  but  i was  right just face  them away . But   to noone seems to know  about  this s/s lead  on the carlin burner   but there is on on the burner at the school im not crazy 

heatmizer

i think its he service man switch

i think its the service man switch  , because where it is in the  series   i know im not exsplaining right ill take pic  tommarrow   and post it