Joking aside, Stratobuddy, you do not have enough experience to fill a system with chemicals and should leave well alone. You will end up causing more damage than good and I recommend that you get a experienced engineer in to do this and follow his advice. That way you'll learn how to do it properly for the next time.
Please don't mess about with boilers either. Adding the wrong chemical treatments is potentially very dangerous. The same goes, for adding chemicals to a heating system. If you don't know where to apply these, you could end up adding these to the domestic hot water system in error, with potentially serious consequences for anyone who comes in contact with them. Remember, many of these chemicals are very corrosive and also very dangerous in the wrong hands.
Please heed this advice as a friendly but knowledgeable warning.