This is my first of many posts and one that I really need some help understanding. I just purchased a new house. The house was built in 1910, but has had multiple add-ons done. Currently there are two furnaces, a really old one in the basement and a slightly newer but still old one on the main floor.
The house is two stories and the basement is just a dirt crawl space for the most part.
This furnace feeds the main floor with floor vents. Pretty straight forward and probably the original design of the heating system.
Furnace (main floor)
This furnaces is where I get confused. It has two primary branches off of it. The first branch goes upstairs and feeds a newer addition that was built in the 70's or 80's. The second branch feeds 3 of the same rooms that the basement furnaces feeds + 2 upstairs bedrooms.
Problem and Question -
What I would like to do is removed the second feed off the main floor furnace and just run smaller duct work to the two bedrooms that it feeds and stop feeding the same rooms that the basement furnace feeds. If I did this am I going to get myself in trouble with "HVAC Laws"? Why would someone design a system like this? Any advice/help would be appreciated.