modernizing gravity hot water heating system
My brother in law has purchased a house in Queens, NY which has an oil fired boiler in the basement and an expansion tank on the third floor that overflows into a plumbing stack. The radiators on the first floor have two pipes entering them on opposite sides. Those on the upper floor also have two pipes going to them but they are yoked together at the radiator and only one pipe enters the radiator. How does such a piping arrangement work and where can I find information about it? How does one go about modernizing such a system?
Thank you, HKristenholz, for your prompt reply. What I meant was that each upper floor radiator has two pipes going to it but they don't both enter the radiator directly. They are joined together on the outside of the radiator and only one pipe enters the radiator. There must be some kind of baffled valve on the outside of the radiator that I'm not familiar with.