I am in the planning stages of installing my Solo 40 in parallel with my existing fuel boiler and need some help. The parallel diagram in the book shows my existing circ. pump coming off my supply manifold, but mine comies off the return manifold then back into the boiler. Do I need a weighted check valve before my pump? I plan on piping my Solo feed into the return of my existing boiler and the return into the supply of the existing boiler. Does anyone have a diagram how they hooked up theres? Thanks for the hlep. Doug