I've checked out "Modern Hydronic Heating" by John Siegenthaler and it is very helpful. I still have the problem of designing a "reverse return" system of pipes. This requires a simultaneous solution of non-linear equations ( head = constant * flow to the 1.75 power )...
Thanks for the reference. I've read about the 20 degree assumption other places. My existing system drops 10 degrees at the most, so that assumption doesn't seem realistic.
I need to replace the heat pipes for a small apartment building. Each unit will be on a separate circuit for zone control. I have a procedure, but it seems very approximate.
Do you know of a reference that would help me determine the flows in each segment for a particular head pressure...
I want to replace most of my existing black iron hot water heating pipes to divide the system into zones. Is it OK to use copper pipes to connect to my cast iron radiaters and to iron pipes? Do I need to use dielectric unions?