To flush or not on closed loop boiler system

Swilson08

I have a well McLain wtgo that's probably 15-17 years old.    I know the original theory was you should never flush a hot water closed loop system as it would put oxygen into the system and cause rust.    Is this still the case? Or do these need flushing these days?    If I was opening the system to replace a pump or do pipe work then I'd probably just flush it since it was open.  But should we be actively flushing these systems every few years or anything ? 

Mad Dog_2

No. Unless you have issues with heavy bacterial growth,  Water 💧 in these closed systems will usually settle in to a nice balance.  Mad Dog