mark3 damper?

hey all,i have a mark3 now,the owners manual says not to use a manual hand damper of any sort with this stove.if any type of damper is to be used only a baro will do.i was wondering if anyone uses a hand damper with any luck?i already have the damper in the stove pipe from my other stove,it didnt seem to do anything with the other stove at all.thx!

I would concurr, I've yet to see a change with my boiler with the hand damper open or closed. But I still use it.