Bleach is commonly used to oxidize iron, or to change it from a dissolved ferrous state to a solid ferric state. Once it is in the ferric state, it can be filtered out with standard filtration, typically in the 5 micron range is adequate. Oxidized iron in your pipes can be a ferric build-up. Using bleach can further lock the iron into the pipes. The same way bleach does not work well at removing iron stains from a sink, but a mild acid does it with ease. Once bleached, the iron can be much harder to dissolve and can give the appearance of having cleaned the pipes. Some people recommend using iron cleaners, CLR, etc for this process, it will work, but from a simple liability standpoint, vinegar is the preferred method. Using an edible item for cleaning makes for a much safer cleaning process. Vinegar takes a little longer, but it is very effective. A one time cleaning with a mild acid will not damage copper pipe that is in good condition. Just like the copper heat exchanger in a tankless water heater, intermittent cleaning will not hurt it.
Hope this helps.