It beggars belief....if you are that interested in the working principles of a central heating system along with vessel sizing and placement then I suggest you seek further education on the subject..
Why should we give away our trade secrets to someone who is too tight to call a professional.
I'm sure you have friends and relatives that will help you out with regard to any costs you may incur when calling someone out.
too tight, eh how do i do this with £70 a week JSA?