If your plumber told you that you did not need inhibitor then he probably did not clean the system either.
Consider using a non acid sludge remover like Sentiner X400 for 3-4 weeks after you have changed your radiator followed by a drain down, a flush with clean water and a fill with X100 inhibitor.
Avoid any cheap brands or "own brands" !
Tony
Consider using a non acid sludge remover like Sentiner X400 for 3-4 weeks after you have changed your radiator followed by a drain down, a flush with clean water and a fill with X100 inhibitor.
Avoid any cheap brands or "own brands" !
Tony