Filling a system and not firing it right away to remove oxygen leads to rust. A boiler
should never be drained -refilled and let sit all summer withouts days
of high firing. There are stop leak products but the metal is thin.

My system has never had inhibitor added, not for the last 30 years anyway.
Not been drained for over 10 years either.
Open tank system so I suppose some new water would have been introduced to replace evaporation.

My thinking is the water will be pretty inert by now. What do you think?

--
Graham.

%Profound_observation%