adding additive to hydronic system?

ron

I have to replace some shutoff valves so I will be draining the system. I am interested in using a corrosion inhibitor additive. How does one add something like that to a hydronic system? And what's a good one that I should use?

setup: WM WGO-3 oil boiler with WM indirect tank, one circulator doing 2 zones having taco zone valves, and a 2nd circulator for the loop between the indirect and the boiler.

flat_twin

Weil McLain included a tube of Sentinel X-100 and a test kit with our Eco boiler. I used a caulk gun, shoved the tip of the tube into a short cut off piece of washing machine hose and threaded it to the low point drain of the boiler. Might be a good idea to test your fill water so you know what you're starting with regarding ph, water hardness and chlorides.

ron

the fill water is city water (which is good to begin with) after passing thru an aquapure AP904 filter.

I might re-relocate my expansion tank in addition to replacing zone valves and shut off valves on the return side prior to boiler. looking for piping ideas to make adding any cleaner/additive to the system easy